Sax just for reference I drilled a couple of 1/8" holes in my thermstate to relieve air before the engine warms and thermstate opens. I have never had to raise the car in any way to burp it when the pump was already in coolant and circulating. I just turned the pump on and topped it off from the back.

I think you have a very tiny head gasket leak, enough to let some very hot gases into the coolant. The symptoms are exactly the same as the ones I have in my Suzuki Samurai. You might think this is a ridiculous comparison, but..they all have cylinder heads, and head gaskets. I've had this happen to me maybe 3 times in my life, and the clue is this..it only starts to get really hot after about 15-20 minutes, and is gradual. What happens is this, in my case. The hot gases get into the coolant, and super-heat them. The slight increase in pressure in the cooling system is allowed to escape through the rad cap in the form of ..gas... Therefore the water level barely drops, but it gets very hot. I am going to change my gasket next week, and I am sure it will cure it. Of course, you have 2 cylinder heads, whereas I have only one..but I still think this is a possibilty. My engine has perfect, and equal compression..I put my hand over the open radiator mouth, and nothing tries to force my hand away.I have no leaks, and a new water pump, belt and thermo. It still does it without the thermo too...no fanbelt slip, fitted an auxilliary electric fan...still gradually overheats..I bet mine is headgasket anyway!! Can't be anything else!!
Nick

quote Originally posted by fierofetish: I think you have a very tiny head gasket leak, enough to let some very hot gases into the coolant. The symptoms are exactly the same as the ones I have in my Suzuki Samurai. You might think this is a ridiculous comparison, but..they all have cylinder heads, and head gaskets. I've had this happen to me maybe 3 times in my life, and the clue is this..it only starts to get really hot after about 15-20 minutes, and is gradual. What happens is this, in my case. The hot gases get into the coolant, and super-heat them. The slight increase in pressure in the cooling system is allowed to escape through the rad cap in the form of ..gas... Therefore the water level barely drops, but it gets very hot. I am going to change my gasket next week, and I am sure it will cure it. Of course, you have 2 cylinder heads, whereas I have only one..but I still think this is a possibilty. My engine has perfect, and equal compression..I put my hand over the open radiator mouth, and nothing tries to force my hand away.I have no leaks, and a new water pump, belt and thermo. It still does it without the thermo too...no fanbelt slip, fitted an auxilliary electric fan...still gradually overheats..I bet mine is headgasket anyway!! Can't be anything else!! Nick

A bottle of Barrs stop leak can patch the problem if it is a very small leak. I've had it work on a couple of vehicles. Well worth the patch till you can save for the repair. I was hoping as I'm sure Sax is that it isn't a head problem. I always check the things that don't cost so much before I dive in head first

what happend when you tried it without the T-stat and with the coolant topped off?

Well, that is entirely possible, Fierofetish. I replaced the intake gasket but not the head gasket - and Yons has already proven that he didn't know how to put everything back together properly. It doesn't sound like an expensive fix, but I might as well throw on some Vortec heads if I am going to tear it down that far.

I'll try everything else that is being suggested before I tear her down - then try some stop-leak like Butter says - then tear it down if necessary. I'm off tomorrow so I'll play around with these other suggestions first.

I did find that there is a timing mark on the balancer, so I need figure out how to put a timing guage on the block to set it. As I face the front of the engine block (through the passenger side wheelwell), where would the mounting holes for the timing guage be? 4 O'clock? 5 O'clock? Oh, and what should it be set at, anyway?

Now it is more obvious why I call this one the "Purple-Pain."

Well, today's run was a good bit better, but not perfect.

I took off the front license tag/bracket and filled the rest of the coolant (since the back end has been jacked up all week. Note - the coolant resevoir was completely full before I started the car, so plenty ran out as it warmed up. I also replaced the carb gasket since the one under there was used for two different carbs (Holley, then Edelbrock) to be sure that there was no leak making her run lean.

After she was warm, I ran her 5-6 miles at a time before stopping at the Pep Boys (for sail panel two-sided tape, a timing marker and a timing gun - which the latter was not in stock) and Advance (who had the radiator stop-leak, but no timing gun ) The temp worked its way up to 210 for the longest time, then after about an hour (of non-steady driving, of course) the temp started crawling as high as 230 before I shut her down.

As soon as I let off the gas, the temp would drop a bit, and I was cruising at 2500rpm or so. I also punched it a few times at speed and notice a small rise in temp then, too.

So, I'll take her for a ride again to see if maybe an air bubble is being worked out, then (if/when the problem persists) I need to decide to either pull the T-stat or add the radiator stop-leak to see one of those was the problem. Not both because I want to know which one helps first.

Question: Every time I start the car after it cools off, I notice water blowing out of the passenger side tailpipe. I'm assuming that's a reason to believe that a small head gasket leak could be the problem like Fierofetish said. I think I'd like to try the stop-leak first, but does it have any side effects like gumming up the cooling system?

quote Originally posted by Saxman: Question: I think I'd like to try the stop-leak first, but does it have any side effects like gumming up the cooling system?

As long as you follow the instructions, no harm should result. Don't overdose it - more is not better. The most susceptible component is the heater core, but I think you mentioned in an earlier post, that you weren't running with the heater plumbed up.

I pulled the rear cap and the coolant was very low. As I added it, it kept slowly going back down. Up front, the coolant filled up the overflow tank and was dripping out under the cap (which never felt very tight) so I put the old vented cap back on (which was also new - but Advance gave me the vented one which is supposed to be wrong).

That stopped the leak at the cap, but coolant kept going into the overflow tank and filled it until it overflowed through the overflow cap. I had to put the rear cap on to stop the flow to the front.

Why are the friggin front caps letting coolant pass into the overflow? The car is on level ground. JEEZ!

Hmmm - maybe I should be buying a Nova cap instead - since it is a friggin' NOVA radiator! Duhh. Only problem is that Yons won't answer any questions and I don't know what year Nova it is from. Thanks again, Steve Yanda at "Yons Racing"! You are killing me with this "only needs the starter installed" car!

My quest for the proper cap begins tomorrow. UNBELIEVABLE! The "Purple-Pain" will survive - despite what Yons did to it...

quote Originally posted by Saxman: ... Question: Every time I start the car after it cools off, I notice water blowing out of the passenger side tailpipe. I'm assuming that's a reason to believe that a small head gasket leak could be the problem like Fierofetish said. I think I'd like to try the stop-leak first, but does it have any side effects like gumming up the cooling system?

If your humidity is lo you may indeed have a gasket leak. Get the kit to test for that. But also you need to fix that front leaking cap. That probably won't let the system to be filled properly. I drove mine today for the first time and the temp was a little erratic from 160° to 210°. Went back and filled it (after level) a little bit more and problem solved, 160° all the time.

I feel pretty confident in saying any kind of leak-sealer for the cooling system will NEVER be a cure for a leaking head gasket. The escaping compression will simply blow out anything trying to block the leak from the low-pressure side. A bit like putting a cork in a fresh coke bottle, and then shaking it violently...the gas will exert pressure on the cork, which is fitted from outside, and blow it straight out. I never recommend rad-seal, etc..it is, IMHO, a very poor fix-it, and blocks the veins in the radiator, and can destroy the seals/ bearings in the waterpump.I seem to remember, many years ago, that a mechanic friend of mine used to put some kind of dye in the petrol, which would then pass through any gasket leak into the cooling system, and confirm a loss of compression by colouring the coolant...but maybe I dreamed of that, and should market it!! !!
Nick

Nick most folks have a habit of "if a little helps a lot oughta fix it" mentality and theres where you hear your stupidist stories about stopleaks. When used properly I have never had problems with radiator stopleak or even plain black pepper for that matter. Yes black pepper will stop a radiator leak too.

I never said stopleak would fix the problem.

quote Originally posted by Butter: A bottle of Barrs stop leak can patch the problem if it is a very small leak. I've had it work on a couple of vehicles. Well worth the patch till you can save for the repair. I was hoping as I'm sure Sax is that it isn't a head problem. I always check the things that don't cost so much before I dive in head first

It can however help you locate the problem.

With the water blowing out the passenger side sounds like the problem just stuck its head out. Blown head gasket or cracked head or both. It could be a cracked block too. Got one of those in the shed. It kept eating cams till it finally showed some milk in the oil and then I knew I had trouble.

[This message has been edited by Butter (edited 12-08-2006).]

My apologies, Butter. I misread your post, and apologise. I thought you meant it would fix the headgasket leak..
Nick

More thanks to you guys for the assist. I know there is much to do that I have not tried yet.

I picked up a 16lb cap for a 74 Nova thinking that would help - and put it on the thermostat housing (rear). I also put the cap I originally got from CSR on the front - and it seemed to keep the coolant from running out without pressure - and let coolant out under pressure.

So, tonight, I drove it with the CSR cap on the front (16lb I assume) and the 16lb Nova cap on the rear. There is no coolant overflow hose on the rear - and nothing leaked out on my run, so I assume I am in good shape keeping it there (but what do I know). Perhaps I just need a sealing cap - not a spring-loaded one, but it may not matter since it is not leaking.

Well, the damn thing still went up to 220 degrees after 15-20 minutes of 50mph driving again tonight - even thought the temp outside was 28 degrees (and I sure missed having a heating system in the car).

If I get a chance tomorrow or Sunday, I'll pull the t-stat completely - though I would rather not. I just think that the system is right, the t-stat should not matter. By fixing the problem by pulling the stat, I think I am only masking another heating problem - if that makes sense.

When I stopped the engine tonight, I could still hear a bubbling/boiling sound coming from the intake area below the carb, but how could an air bubble be forming in there?

I didn't notice any coolant coming out of the pipe this time, so maybe that is a good sign, Butter.

I'll let you all know how the no-thermostat method works later. It's time for a break. This is too frustrating! I just need to step back for a little while and let it breath before I end up selling it in frustration.

Actually, now that I put up my main thread listing what has been fixed and what still remains, there are no hidden secrets. Everything about this car is out in the open - no surprises. So, the first $6500 gets it (delivered up to 100 miles from 206010). Otherwise, I'll get back to playing with the Purple-Pain tomorrow.

Now, where's my beer...

Saxman,
Several people (myself included) have mentioned or asked whether you have an AIR DAM on this car.
If you replied, I can't find it.

quote Originally posted by HarryG:Saxman, Several people (myself included) have mentioned or asked whether you have an AIR DAM on this car. If you replied, I can't find it.

I thought I mentioned it somewhere. Since I have a Nova 4-core radiator, it is much taller than a Fiero radiator and hangs down as far as the Fiero air dam did. There is no place to add the dam since anything below it would scrape the ground. I figured that the extra radiator hanging down would cool even better than an air dam because it is part of the radiator instead of just plastic.

Does that sound right? Thanks, Harry!

quote Originally posted by Saxman: Since I have a Nova 4-core radiator, it is much taller than a Fiero radiator and hangs down as far as the Fiero air dam did. There is no place to add the dam since anything below it would scrape the ground. I figured that the extra radiator hanging down would cool even better than an air dam because it is part of the radiator instead of just plastic.

Aha! The purpose of the dam is to create a high pressure area below the radiator, and it (the dam) needs to extend across the whole width of the car to do that. Otherwise, a lot of air will just flow around the sides of the radiator rather than flowing up through it.

You probably need to rethink the whole radiator installation. A full-width air dam that passes behind the radiator would almost certainly help. If you don't already have one, a (front) hood vent would definitely help as well.

Have you tried to measure the temperature of the water leaving the radiator when your engine begins to overheat? If there's not much drop in the coolant temperature as it flows through the radiator, your problem is definitely insufficient airflow. On the other hand, if you measure a good drop in coolant temperature through the radiator, the problem is most likely poor coolant flow. Even if you have to buy a couple of thermometers, diagnosis like this is a lot cheaper and less frustrating than throwing parts at the problem.

[This message has been edited by Marvin McInnis (edited 12-09-2006).]

quote Originally posted by Marvin McInnis: Aha! The purpose of the dam is to create a high pressure area below the radiator, and it (the dam) needs to extend across the whole width of the car to do that. Otherwise, a lot of air will just flow around the sides of the radiator rather than flowing up through it. You probably need to rethink the whole radiator installation. A full-width air dam that passes behind the radiator would almost certainly help. If you don't already have one, a (front) hood vent would definitely help as well. Have you tried to measure the temperature of the water leaving the radiator when your engine begins to overheat? If there's not much drop in the coolant temperature as it flows through the radiator, your problem is definitely insufficient airflow. On the other hand, if you measure a good drop in coolant temperature through the radiator, the problem is most likely poor coolant flow. Even if you have to buy a couple of thermometers, diagnosis like this is a lot cheaper and less frustrating than throwing parts at the problem.

The Air dam stuff is BS if the fan is working. Car sitting still with an electric CSI water pump and the fan working up front you can watch the temp hand go down if the radiator is stock and the temp has been run up to 220 - 230 degrees.

What is the flow rate of your electric water pump? Some were only made for drag racing short runs and may not flow enough for continuous operation. The heater core not being hooked up might be an indication the V8 mod was just for racing.

[This message has been edited by Butter (edited 12-11-2006).]

quote Originally posted by Butter: The Air dam stuff is BS if the fan is working.

Seems logical ... assuming the fan is correct for the application and is installed and working correctly ... but still not guaranteed unless there is actual data to support it. A temperature drop test, as I described, will tell the tale. There is no substitute for your own data.

From what Saxman has posted previously, whether or not the fan is correct for the application and correctly installed is open to question ... given all the other shoddy things he's discovered on the car. I believe he has said that there is no fan shroud, which will substantially reduce the amount of air that the fan pulls through the radiator core.

[This message has been edited by Marvin McInnis (edited 12-11-2006).]

There are two kinds of caps- vented and non-vented. Your rear cap should be non-vented.

See, when the engine (& vented cap) is cold, there's no seal. As it warms up, the cap seals. As you drive, there might be some flow into the overflow bottle. When it cools down, there's a vacuum in the system, 'cause what flowed out of the tank ain't there any more. When the cap cools down enough, the seal is broken and water is sucked back into the radiator from the overflow pipe.

If your rear cap vents, then the water in the system that's above the front cap will run into (and then out of) the overflow tank. Your coolant system above the front cap will contain only air vented into the system by the rear cap.

Thanks again for the advice. The back cap is leaking just a few drops a minute - and only after the system gets really hot, so I will look for a deeper cap.

I took the t-stat out last night and drove the car tonight - and took Doc- for a spin. The temp still did the exact same thing as always - creeping up to 210 easily - then slowly towards 230.

I still have some "Water Wetter" to try - and "Doc" pulled the vacuum "stalk" (where the small lines go into the intake) and put some thread sealer on it in case it was leaking (it was a little loose).

It was too late to run the car to see if the vacuum leak was the problem (since the kids are in bed and the people in this neighborhood aren't used to muffler-less V8's after dark) so another run will have to wait until tomorrow.

Timing may also be the culprit. I have the timing tab now, but have to figure out where to put it. I can only see the bottom of the balancer through the wheel well, but I have the feeling the timing mark will need to go near the top. I have heard of others putting the mark on the other side of the balancer and using the #4 plug wire, so I will have tot look into that.

Carb adjustment is also another possibility (in addition to all the other suggestions you guys have come up with), so that is on the list.

A dual-fan setup may be needed, too. I still have not measured the temp difference going into the radiator compared to the outgoing coolant. It's on my list (if nobody buys it from me first).

It sure would be nice to get back to work on the Fino instead of this one. It's taking too much time in becoming my fun-drive-to-work ride! Anyone want to take over?

quote Originally posted by Butter: The Air dam stuff is BS if the fan is working. Car sitting still with an electric CSI water pump and the fan working up front you can watch the temp hand go down if the radiator is stock and the temp has been run up to 220 - 230 degrees. What is the flow rate of your electric water pump? Some were only made for drag racing short runs and may not flow enough for continuous operation. The heater core not being hooked up might be an indication the V8 mod was just for racing.

I think it is a 37gph pump - so that should be fine I have heard.

This may have been covered already; but just in case it is has not with your never-ending-overheating problem: Have you felt all of your return hoses when it's hot? Sometimes you can get one (especially and old one) that will collaps some when hot and restrick the water flow and the hotter it gets the more it collapses. When hot squize them with a glove they should not feel overly soft. If so, you may need to put a spring in one to ensure that it stays open. I'd tell ya not to worry about it and to just chill-out but it seems you can't. Good luck!

heh heh. I have to chill out for a while. Christmas is almost here!

All of my hoses are solid (except the joints) so collapsed lines should not be the problem. I have to check the lines to be sure that none of the original solid return lines are dented, though. I haven't done that yet.

Good point, Francis T!

It SEEMS that since the t-stat was removed and there was no change AND you can see the coolant flowing in the correct direction, then it looks to be an air flow problem. Might look at checking the temp drop (as suggested before) at the radiator before spending any more money. With the hood open for max airflow, fan wired on, see exactly how much drop you get. (I'm talking a meat thermometer placed on the line coming in, check temp, then move it to the line out. Nothing scientific, just a rough look)

If the head gasket is blown, shouldn't you get air bubbles in the coolant? You still got air in there? With the front cap off, engine running, you would see air bubbles being pushed through the system, wouldn't you?

[This message has been edited by Hudini (edited 12-14-2006).]

I would think that a leaky head gasket would either foam up you coolant or dirty up you oil. And I thought you already check for squished coolant lines! When I stared on my 87GT and went to undo the coolant drain plug, sure enough some halfass machanic had jacked the car up by it and nearly flattend it all the way, surpisingly it never overheated? Now if it were a V8............

quote Originally posted by Hudini: It SEEMS that since the t-stat was removed and there was no change AND you can see the coolant flowing in the correct direction, then it looks to be an air flow problem. Might look at checking the temp drop (as suggested before) at the radiator before spending any more money. With the hood open for max airflow, fan wired on, see exactly how much drop you get. (I'm talking a meat thermometer placed on the line coming in, check temp, then move it to the line out. Nothing scientific, just a rough look) If the head gasket is blown, shouldn't you get air bubbles in the coolant? You still got air in there? With the front cap off, engine running, you would see air bubbles being pushed through the system, wouldn't you?

Sorry I haven't moved faster with this one. Kidney stones are kicking my a$$.

I haven't run the pump with the front cap off because it is much lower than the rear cap (rear is up on 2x8's so I can get a jack underneath) - so coolant just flows right out - even when cold. I'll have to move her to check that one soon. I DO need to check the temps on in/out lines this weekend - after checking the lines under the car for dents .

You are both right - I am not seeing any air in the system after it cools down, so I hope that means no haed-gasket leak. The oil looks clear as the day I put it in, so that is another good sign.

Hood open does not cool it when she is idling. It just wants to stay around 210 even when sitting still. I wonder if I should go with a double-fan if these other cheap fixes fail.

I'll try some more on Saturday (starting under the car!) Thanks!

From your description it sounds more and more to be related to the radiator. Either air flow (no air dam, no shroud, 1 fan, etc) or the radiator itself. The 2 fans with a full shroud should fix it assuming the radiator is working properly, IMHO. (Man I hate replacing parts until I get the right one. But then again, I'm a shadetree mechanic)

I only had a little while to play tonight, but I know that Water Wetter and tightening up that vacuum "tree/union" did not make a difference.

I did see that the temp difference between the upper and lower radiator hose were noticable as it warmed up. When the upper one was too hot to touch, I could still hold on to the lower one. I had no time to check it with a meat-thermo afterward, though.

Also, the temp would go up under acceleration only - but would not come down as much under idle - so the temp did go up as long as I held the gas down. More RPM made more heat (naturally) but the temp would only drop a couple degrees at idle again - no matter the wind speed.

I still need to get under the car to check the lines. I wonder if those corrogated metal hoses have anything to do with the temp problem?

Dual fans with a shroud that covers the entire radiator to make sure the cool air is pulled through and not just recirculating hot air.

I still think you have some problem with your system somewhere, like a restriction, but his idea of that temp gauge on the inlet and outlet hoses for your radiator (meat thing) is a good one to try.

I should be able to try that one this weekend.

I pulled the rear cap to put in the Water Wetter before that last run and coolant ran to the front overflow tank again. The front cap just let it all go through. Is that normal? It didn't leak around the cap - it just went through to the overflow tank. That does not seem right to me, but I guess the coolant has to get back in the radiator when it cools off.

Hey Sax,

I've read a few replies regarding a possible head gasket leak. In many cases (similar to yours), even a small head gasket leak is going to result (especially after all of the time you've been dealing with this issue) in Hydrocarbons / exhaust gases in the coolant. They used to make little paper strips that you could just dip into the coolant. It would change colors if there were HC's present in the coolant. Now many radiator shops have HC testers that they just stick into your overflow tank.

It may be worth a shot to find out if anyone local to you has a tester. You could always just run a sample of your coolant over to have it checked out. At least if you find that you have HC's in the coolant, you would be able to remove the heads, check the deck surface and head mating surfaces (if using the same heads) and replace the head gaskets. Who knows, after all of this time bleeding, burping, thermostat removing etc, it would be a real pain to find out you have a head gasket leak.

From an old TSB I had saved on the work PC:

<Paste>

Common symptoms:
Overheating, often when slowing or stopped after extended high load driving. The overheating can be seemingly random and sporadic.
Bubbles in coolant overflow reservoir, immediately after running. Sometimes very small.
Eventual Sludgy residue in coolant overflow tank.
Hydrocarbons in coolant overflow tank, this is tested by a mechanic with specialized equipment and is not evident visually.

[This message has been edited by 3084me (edited 12-16-2006).]

Yikes, coolant should never just run freely into the overflow tank with the cap on tight. Maybe you have a bad pressure cap that does not let the system pressurize correctly. (assuming the engine was cold?) You sure about that Nova radiator?

That test sounds like an easy check. I'll take some coolant into town next time I am out. Thanks!

Yons still won't answer me about the radiator (or anything else), so I don't know what year Nova cap to get.

The guys at Advance and Autozone can't help - of course - without a year or part number. The one I tried is for a 74 Nova but I guess the plunger does not reach deep enough. It's just trial-&-error with these caps for now...

Saxman, After running my Samurai for the last week with my overheating problems, I have to stick my neck out and say it is ,just like mine ,DEFINITELY a head gasket leak!! After leaving the Samurai ticking over for 45 minutes whilst running some coolant system cleaner through it, and it didn't overheat..and then took it for a 15 minute spin..it overheated again!! I checked the overflow bottle...empty!! Opened the radiator cap, and there was only enough room to top it up with a cupful of water !!! No water in the oil, no oil in the water..no slipping belt, good water pump , no thermostat...exactly the same as you!!
I have just won a full gasket set on eBay for £27 (£105 in Spain !!), and will be removing the head and getting it skimmed as soon as the gaskets arrive..and I will let you know the results. Try the hydrocarbon test if you can...can't find anybody here in Spain to do it. But I know for sure it is my head gasket..even say it is on cylinder 4....
Nick

Like I said before, measure how deep the cap is. If it's higher than the hole to the overflow tank then it's the wrong one and like not having one at all.