Does anyone know any problems that the 4.9L Cadillac engines have? I am going to be doing the swap and i was talking to a guy about it and he told me that the engines had problems with the head gaskets and the intake gaskets. Just trying to follow up on some of these problems before purchasing the engine and tranny.

Thanks you
Andrew

quote Originally posted by Fieroboy87: Does anyone know any problems that the 4.9L Cadillac engines have? I am going to be doing the swap and i was talking to a guy about it and he told me that the engines had problems with the head gaskets and the intake gaskets.

I've not heard of engine gasket problems being typical with that engine. Perhaps your contact is confusing the 4.9L Cadillac V8 with some other engine?

In any case, you might benefit from contacting the folks at The Fiero Factory ( http://www.thefierofactory.com/services.php ).

They've completed dozens of 4.9L Cadillac V8 engine swaps in Fieros, so if a problem with 4.9L engine gaskets was commonplace, they presumably would know about it.

Separately, my response to your inquiry hopefully also will help to elicit for you some responses to your inquiry from others on this forum.

Good luck to you on your engine swap project!

The gasket problem was with the 4.1s and maybe the earliest 4.5s.
The 4.9s were quite reliable by the time they had evolved that far.

I've got a 4.9 in my Formula. The only real gasket problem I've ever had was with the water pump.
I think the first time it was replaced (before I had it) the small 10 mm nuts around the perimeter were tightened by a 500 lb. robot gorilla.
Bent the timing cover and ultimately pulled one of the studs through the cover.
The crank seal also looked like it had been squeezed in using channel locks. Needless to say, it leaked like an old rowboat.
Fortunately, all of that stuff was fairly easily replaced.
No head or intake gasket issues at all.

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Raydar
88 4.9 Formula IMSA Fasback..........................88 3.4 coupe -soon to be something other than red

Read Nealz Nuze! Praise the Lowered!

It was the 4.1 with the problem, usually around 100,000 miles.

I've been running a 4.9 for 7 years now with no gasket problems. I also have not heard of any problems.

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC build underway
88 Formula/GT 4.9 Allante Intake (My Baby)

My 4.9 swap is now 3 years old. The donor drivetrain had 82K on it and has had no issues. I beat on it on a regular basis and it just keeps coming back for more. If you source a good engine to begin with, and do a quality install, I doubt you will have any issues.

The problem I have had with my 4.9 is the same I've had with my v6's.
Cruising in gear near idle, the engine seems very sensitive to O2 fluctuation and starts to buck.

quote Originally posted by Raydar: the small 10 mm nuts around the perimeter were tightened by a 500 lb. robot gorilla.

I think that same robot gorilla did the last oil change on my red Escort before I bought it. Both drain plug and oil filter were on so tight I had to destroy them to get them off.



Ed

I have an 88' 4.5 in my 88' Formula and I did have to replace the intake gasket. But I think that was partly due to the engine sitting around for a couple of years in a garage. I think it just dried out.

Before I put my engine in, I did replace the water pump and all related seals. Nothing seemed like it leaked or was going bad, but why not while it's all out and easy to do? Engine has about 98k on it now. Hammer on it, comes back for more, last mpg figure I pulled was 23.4 mpg average. Hard to beat for the fun factor it provides.

If the engine you're getting is a good running unit, I probably wouldn't worry about intake or head gaskets. Although I did find out something interesting. The Dexcool that's suppose to be used in aluminum blocked engines eats older gaskets produced before Dexcool came out I think in 1995? So our 80's cars/engines sometimes don't have gaskets with material that likes the Dexcool. My new intake gasket was a greenish/blue color which is Dexcool approaved and will last forever so I'm told.

-Dan

quote Originally posted by lou_dias: The problem I have had with my 4.9 is the same I've had with my v6's. Cruising in gear near idle, the engine seems very sensitive to O2 fluctuation and starts to buck.

With the 4.9 this is usually contributed to the ISC motor. There is a setting in the memcal that can be changed to help eliminate this.

Basically there is a setting for a "desired idle". This is the engine speed that the PCM tells the ISC motor to use until the vehicle speed is below 5MPH (then it drops to your idle speed). I believe around 1350-1500rpm in a stock chip. This can be adjusted down and probably should be though I wouldn't go below 1000 for fear of some stalling issues with a sudden throttle drop (ISC lag time). Its usually more of a problem for manual cars. Adjusting shift points can also help for auto cars by not allowing it to be in gear at that low of RPM (also done in the chip). Hope this sheds some light on the situation.

As for the 4.9 gasket problems I have never heard of any. Earlier 4.1/4.5's and early Northstar have had these problems though. The 4.9, to me, seems to be a very solid motor all around.

[This message has been edited by Fieroseverywhere (edited 07-24-2009).]

I have been running a 4.9 for 6 years now and only 1 water pump gasket that I had to replace.

Jack

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If you can not run with the big dogs, stay on the porch!

As an after thought, I was at my salvage yard today. He said it would be tough to locate a 4.9 with under 100,000 miles, and at 200,000 a lot of them will have water in the oil from said gasket problem. At 200,000, all bets are off on most engines.

[This message has been edited by weaselbeak (edited 07-24-2009).]

quote Originally posted by Fieroboy87: Does anyone know any problems that the 4.9L Cadillac engines have? I am going to be doing the swap and i was talking to a guy about it and he told me that the engines had problems with the head gaskets and the intake gaskets. Just trying to follow up on some of these problems before purchasing the engine and tranny. Thanks you Andrew

he is confusing the 4.9L engine with the Northstar engines that use Dexcool (early formulations of dexcool slowly dissintegrated head gaskets). the early 4100HT engine had all kinds of problems, but by the time the 4.9L engien came out, all the problems of that engien platform were worked out.

Got the engine today

quote Originally posted by weaselbeak: As an after thought, I was at my salvage yard today. He said it would be tough to locate a 4.9 with under 100,000 miles, and at 200,000 a lot of them will have water in the oil from said gasket problem. At 200,000, all bets are off on most engines.

go to car-part.com and search for one in your state

FYI
I looked under the hood of a 70's something rear drive Cadillac with a 4.9 liter iron block the other day. Not surprisingly it looked nothing like the 4.9 being discussed here.

quote Originally posted by gem1138: FYI I looked under the hood of a 70's something rear drive Cadillac with a 4.9 liter iron block the other day. Not surprisingly it looked nothing like the 4.9 being discussed here.

Those are not 4.9s, they are the 307 cubic inch cast iron Oldsmobile engines.

quote Originally posted by stickpony: that has nothing to do with O2 sensors bro, its most likely a fuel pressure/delivery problem, spark delivery problem, or an ISC motor issue. didnt you have isc motor problems Lou? i remember you hada thread going a while back trying to nail down the problems...

It seems I have nothing but problems with this car. When the turbo motor was in, it did the same thing. The only thing they'd have in common is the fuel pump.

quote Originally posted by lou_dias: It seems I have nothing but problems with this car. When the turbo motor was in, it did the same thing. The only thing they'd have in common is the fuel pump.

Did you ever get this all worked out Lou...??? I also have a 4.9 in my GT w/ no issues so far... (knocks on wood)... I was verrry lucky to find this engine as it only has 33k original miles... With these low miles no issues at all, but we will see later. SmoothGT

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Steve
aka. SmoothGT
NotAFieroAnyLonger
CURRENT BUILD:
" SmoothGT-'w8nc' "
1987 Fiero V8/hybrid
1995 Lexus SC-400