Yes, and also Cliff... get new heater core hoses. There are two, and they're not very big... I just tried looking them up and my head hurt. But basically they're two (less than 1 foot long hoses each) that connect the heater core to the two smaller coolant pipes that run the length of the car next to the gas tank (not to be confused with the big ones that run under the sides of the car).
If you've never replaced your heater core before, then you'll likely end up destroying the hoses (or they are already destroyed) when you remove them... and you'll want to have them replaced anyway. Easiest way to get them off is to slit them down the side with a razor, and then you can just peel them off the heater core outlet/inlet.
They should be like $10 bucks each. They are specifically molded for your car, but they sell replacement hose cheap at the local auto parts stores (at least here in the US). The majority of the cars I've seen here in the US that are that old, they usually just replace them with these aftermarket "one size fits all" hoses.
I've replaced numerous heater cores on several Fieros over the years and never had to replace a hose yet. I find that the hoses have more than enough extra length to easily allow the sacrifice of a half inch (or more) during removal. I make a very short slit, stick a small pick under the rubber to get it partially loosened, and then grab hold with my hand and twist that sucker right off.
The hoses are not held on with clamps, they are crimped on to the aluminum heater core lines.
Joe, are you sure? Is it perhaps different for '88? As stated in my previous post, I've never replaced a heater core hose. However, earlier this year I was dealing with a slight coolant leak with my Formula. I took this photo of it, and not only are the clamps obvious, but there's even a ridge evident on the metal tubes indicating where the rubber hoses need to be pushed up to. I'll admit that I have no way of knowing this car's previous history prior to my acquisition in 2013, but judging from the rest of the car, I'd be surprised if these heater core hoses were not original.
Patrick, you are correct. I just checked an original low mileage 88 GT that's on the rack in the shop. It's only got 31K on the odometer and the hoses are clamped at both ends.
I have replaced a non -A/C heater core 3 times in my over 20 years owning Fieros. And 2 on the same car. The issue is the heat will stick the hose to the copper core tube. Making it very difficult to remove and lots of effort and muscle to remove. Something I just tried this year on installation of the new heater core is to apply silicone grease on assembly of the hose. This might make dis-assembly easier than a Fiero with a fail heater core with less than 10,000km. But was replaced 13 years before. My conclusion is I probably had old / contaminated coolant. I still believe the coolant was original coolant or from 1994 or earlier. That’s really old. I did flush the coolant completely, and put new 50/50 Peak antifreeze. (Green)
As the title says, I found another coolant leak. It's coming from under the dashboard, passenger side so it's the heater core.
So yeah, that was the last time I drove the Fiero. There were only a few drops coming from under the passenger's side dashboard.
Today I was on my way to a birthday. First time I drove it since Thursday. After about a mile I see my temp go up like crazy, past the red. And steam was coming out of the vents. So I quickly parked the car. Looked under the car and saw it was loosing a lot of coolant. Now the thing that suprises me, is that there wasn't much coolant leaking under the dash. Everything came out from under the car. So did the heater core fail, or the hoses, or what?
I still need to get the car home so I can work on it. So what is the best way to bypass the heater core? Can I simply loosen the hoses and plug them? Or do I need to connect the hoses together?
And do I need coolant or can I just use tap water (just to get it home)?
So what is the best way to bypass the heater core? Can I simply loosen the hoses and plug them? Or do I need to connect the hoses together?
Do not just plug the heater core hoses. (See the quoted post below.) Connect the two hoses together. Years ago, I used a 1/2" copper elbow (after previously having used a too-restrictive fitting) when I was in the same situation as you. That worked just fine.
In regards to adding water or coolant... doesn't matter, but water of course will dilute the antifreeze.
Back in the summertime, my heater core started leaking. I didn't need the heater at the time, so while I was tracking down a new core, I bypassed the leaking heater core by disconnecting the two rubber hoses from the core and re-connecting them to each other. However, between the two hoses I used a fitting which had a very small passageway for the coolant to go through. When I got the new heater core, I flushed out my system and I was very surprised at that time to discover my thermostat looked much like it does in the picture below. I didn't understand at the time what the heck had happened to the thermostat, so I just bent it back into shape and re-installed it. Unknown to me until the cold snap here revealed a problem, the thermostat arms bent again from "normal" water pressure in the system (because the thermostat "arms" were now weak from being previously bent).
So in retrospect it's now easy to figure out what happened. The fitting I used to temporarily connect the two heater hoses to each other restricted the coolant flow way too much and this resulted in higher than normal coolant pressure pushing against the thermostat. The long thermostat "arms" therefore bent. Lesson learned!
[This message has been edited by Patrick (edited 09-30-2023).]
Patrick that was not what caused that. Think about it - the heater core is shut off by the heater control valve when you don't want heat. I bent several thermostat retainer handles just for hitting 5000 rpm.I eventually rebuilt my thermostat housing and now use an S10 thermostat and solved the problem. sleek
Are they on rockauto perhaps (since I'm going to order the heater core from them anyway)?
I'm sorry Cliff, I spent like 10 minutes on Rock Auto trying to find them, and for whatever reason I couldn't find them, so I don't even know if I mentioned that in my response.
Going through my spare parts for my daughter's car... I remembered that Rodney Dickman does in fact sell replacement hoses. It really depends on how bad yours are... but when I last replaced a heater core in a Fiero, my 87 Fiero had 120k miles on it, and those hoses were swollen and beat up... and I had to replace them (you could just order them at any auto parts store at the time).
Here's the link for Rodney Dickman's heater hoses:
It's w/ AC... I think you said you don't have A/C though. The hoses should still fit, they'll just be a little bit longer is my guess. But you can e-mail him to make sure.
Connect the two hoses together. Years ago, I used a 1/2" copper elbow
The closest I can get here is 12mm (or 0.472").
quote
In regards to adding water or coolant... doesn't matter, but water of course will dilute the antifreeze.
I'm not too worried about the antifreeze getting diluted since when I'm going to replace the heater core, I'll probably loose a lot of the coolant anyway and filling it up with proper coolant again should make it a lot less diluted. Our winters aren't as cold as they used to be and it seldomly drops below 20*F.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Originally posted by Cliff Pennock: I'm not too worried about the antifreeze getting diluted since when I'm going to replace the heater core, I'll probably loose a lot of the coolant anyway and filling it up with proper coolant again should make it a lot less diluted. Our winters aren't as cold as they used to be and it seldomly drops below 20*F.
Doesn't matter how cold weather is. You need 50/50 mix just to have correct level of anti-corrosion etc so won't leak because parts rotted inside out.
I was looking at an 84 diagram which has a control valve with a bypass.
An '84 diagram for what?
Just to be clear, there was no Fiero of any year with a valve to control coolant flow through the heater core. Regulating HVAC heat has always been done by controlling air flow through the heater core.
quote
Originally posted by sleek fiero:
sorry for being misleading.
No problem, it's not the first time that somebody has mistakenly suggested here that coolant flow through the Fiero's heater core is controlled by the HVAC. I just didn't want anybody misled.
I'd guess that's close enough, especially just to get the car home... but anything you can use as close as possible to the ID size of the hose would be best.
So armed with a 1/2" copper pipe, a pipe cutter and some knee joints, I tried to temporary fix the car. Turned out it wasn't 1/2" but 3/4"... 😭
But, I also saw this is probably going to be the easiest repair I ever did on my Fiero so I decided to wait for the heater core to arrive (which according to the Fedex website will be Wednesday) and just replace the heater core where the car is now.
One thing did surprise me however. When I took of the (insert name of that thing that runs along the length of your front window), and got a clear view of the hoses, I saw this:
What the heck is this? Who put that in an what for? It says "Keep tight. Flush Fill Connector"
The complexity of the Fiero coolant flush (draining and filling) procedure in the manual by cleaning out ALL the old coolant requires several flushing’s until the drained liquid is nearly colorless.
But some people will use 'this' fitting (like on your car) is an 'easier' way to flush the Fiero coolant system. A person can now flush the coolant by connecting a hose (clean water) and opening the coolant system (radiator drain) with the engine running.
But to me, it is a 'bad' idea as 'tap' water can contains high levels of dissolved minerals; I ALWAYS use distilled water to flush my coolant systems.
EDIT: Inspect your coolant system and check for another 'cap' to open the system as this person who installed the coolant flush fitting, maybe installed another 'drain' too.
IMHO (which means that some members want to argue about MY views)
Below is MY V6 Coolant Draining Procedure: ------------------------------------------------------------- *DO NOT try to open the plastic radiator drain valve; the plastic stem often breaks, or the threads get galled. Leave the plastic radiator drain valve alone.
*I don't try to open the two drain plugs built into the coolant pipes under the car as these plugs are normally very tight (frozen) and their inter socket of these plugs will strip.
*I don’t waste any time on the V6 engine block drain plugs either as aren’t accessible (one is under the starter) and ineffective as considerable amounts of coolant can remain in the block. (BTW: Some members will remove the starter and will attempt to flush the block.)
The passenger coolant pipe under the car, and 3-inches rearward more from the drain plug; remove the rubber hose (heater core) from the main pipe to start draining the coolant. Leave the radiator and engine/thermostat caps on. After the coolant drained; open the caps and remove the thermostat.
Without the Thermostat: *Install the rubber hose (heater core) back on the main coolant pipe *From the Thermostat Housing; pour distilled water watching the radiator opening, when fill, cap it *Pour distilled water to fill the thermostat housing, and then cap it enough to seal the housing *Run the engine 30 seconds, shut it off, open the engine cap, add distilled water and cap it tightly *Run the engine at least 10 minutes to circulate the liquid, and then shut it off to cool it down
*Drain it again and fill it up repeatedly until the drained liquid is very clear. (On my GT is around ten times)
Install the rubber hose (heater core) back on the main coolant pipe. Remove the coolant recovery tank, clean it and reinstall it.
Filling Procedure: Keep in mind, the cooling system fluid capacity is 13.8 quarts and the fully flushed coolant system has ~7 quarts of Distilled Water in the engine block. The next step is to pour ~2 gallons (8 quarts) of straight full strength concentrate antifreeze, not a premixed 50/50.
------------------ Original Owner of a Silver '88 GT Under 'Production Refurbishment' @ 136k Miles
[This message has been edited by Vintage-Nut (edited 10-02-2023).]
And been on there for Decades & can leak or break if you mess w/ it now.
I & many others hate them because they break often w/o warning. Often don't work very well either. + maybe Illegal in some places as users often dump coolant on the ground, in sewers, etc.
[This message has been edited by theogre (edited 10-02-2023).]
One thing did surprise me however. When I took of the (insert name of that thing that runs along the length of your front window), and got a clear view of the hoses...
I don't know what it's called either, but are you referring to the tray/support that holds the sunroof while stowed up front?
Replaced the heater core today and I'm happy to say that that fixed the problem! So fortunately, there were no other leaks. This was probably the easiest repair I've done to my Fiero so far. 😊
Haven't tested yet if this also fixes the temperature gauge going all over the place, but it could very well be. The leaking heater core of course not only leaks coolant, but also sucks air into the system.
Likely Will need a few heat cycling to get all air out. No matter how follow "burping" methods many still believe you need.
Likely Won't help the gauge bouncing. All "Dumb" Gauges can/will bounce depending where/how you drive, weather that day, etc. & more so on Fiero w/ ~ 3x system capacity.
No, I meant the temperature quickly rising to beyond the red, stay there for a few seconds, then drop again. Which might be caused by an air bubble in the system. If I drive normally, the temperature stays pretty constant (around 175*F). But I only had to floor it once and the temperature would immediately rise to beyond the red. After which it would drop within seconds to 175* again, only to slowly rise to beyond the red again.
Originally posted by Cliff Pennock: No, I meant the temperature quickly rising to beyond the red, stay there for a few seconds, then drop again. Which might be caused by an air bubble in the system. If I drive normally, the temperature stays pretty constant (around 175*F). But I only had to floor it once and the temperature would immediately rise to beyond the red. After which it would drop within seconds to 175* again, only to slowly rise to beyond the red again.
Bouncing like that can happen w/ OE type T-stat & 175°F isn't even opening the T-stat.
& Again you cannot trust that gauge. Should use ECM scanner that reports all sensors Way Better then Dash Gauges that often have crap power, crap grounds, crap 1 wire to whatever sender, or all three.
Air in the H-core is purge when you start the car & have T-stat In. Sometimes... If H-core is installed wrong may trap air but only problem is little to no heat to cabin. H-cores have 2 sizes of hose/tube joints to prevent that. Air in the system then is pushed to the Radiator then out thru Overflow tank as system gets heat cycled.
see cave coolant section. Now Stant is gone for aftermarket so Can't get the SuperStat that was made to stop or reduce gauge bouncing.
), it really opens up access.
