2.5 Tech 4 What oil?

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I just picked up a 1990 Cutlass Calais with the 2.5... It was my great aunt's car who quit driving (she is 91). It has 132,000 on it, my cousin (who was in charge of work done on car) told me the bottom end had been redone, but not the head. Upon replacing the valve cover gasket this confirmed that (lots of deposits). He bought the car off someone else recently though so the history is a bit sketchy. The engine sounds noisy, but they all did. I was thinking of using of PZ Longlife 15W40? It's a $350 car, so I don't want to get crazy. What oils do these things like?
 
I would run an Auto-Rx first to clean out the motor. Find the dino on sale, Pennzoil, Havoline, Chevron. Even Supertech would do ok at 3K OCI.
 
Another Iron Duke owner.
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Mine is an 88 Grand Am with 194,000 miles.

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My engine looks like this:

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No problems really, unless your looking for synthetic, Chevron and Havoline are great.

I wouldn't run a valve cover gasket though. Every one I've had leaks. The valve cover was designed for just a bead of RTV.

See this thread here:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=24;t=001063#000000

-T
 
I agree, run two Auto-RX cycles (made a big difference in my van), then any high-mileage oil would be fine.

Everybody who recognizes the significance of his screen name, raise your hand.
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I got rid of a Buick Somerset with the 2.5 at 235,000 miles that got nothing but 5W30 Valvoline. It sounded like a diesel from day one. You are right about the valve covers, they leak unless you use a good gasket sealant. The guy that bought the car from me said it burned up going down the road at about 300,000. He said he never fixed the valve cover leaked and apparently the oil caught fire and burned up the car. Bottom line is these things will run forever with any decent oil.
 
I had an 88 Grand Am and the 2.5L Tech-4 seemed to hold best oil pressure on Valvoline MaxLife, and it also stopped the valve cover gasket leak. It got 10W-30 in the warmer months and 5W-30 November-April. It was a great engine, even sounding like a diesel. It still clatters around to this day with over 200K. Yes, the clattered and sounded like diesels, but that design didn't get 'iron duke' for nothing. I think that 2.5L design was used in 70's and 80's jeeps. Great little engine! The one I had didn't use oil, after the MaxLife stopped the valve cover leak. Good Luck!!
 
Johnny-O must a big fan of custom cars!
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This was posted from another forum, I don't want to take credit: Some history of the Iron Duke...

Okay...early motors, such as those used in the Chevy II (153 cid) are basically a 194 six cylinder with a couple of cylinders missing. They share the basic design characteristics with the 194-230-250-292 six poppers, and there is even some parts interchangability among them.

The 153 had a reputation for shakey idle quality, but was very reliable and ran forever. They were used in some Mail Jeeps up until the very early 70s, and saw some use in light marine applications as well. Those early motors incorporate a common small block Chevy bellhousing pattern so tranny choices are wide open!

In the mid-late 70s, the motor found it's way into small GM cars such as the Monza, Sunbird, Astre, Skyhawk and some Vegas here and there. This was the 151 variant...still carbureted and it retained the V8 bellhousing pattern and most design features of the earlier motors.

Then, in the 80s, the motor began showing up in front wheel drive GM vehicles, as well as in the S10/S15 trucks and even the Camaro/Firebird line-up for a few years. These engines were re-designed to use a cross-flow head and a FWD bellhousing pattern. Pretty soon, they were fuel injected and touted as the "Tech 4" engine found in so many front-driven cars and Fieros.

For most projects we'd be interested in, the earlier motors with the V8 bellhousing is probably more desireable than the later ones, although by using an S10 or F-car tranny, rear wheel drive swaps with the later cross-flow motor are a fairly simple deal, too.

The engines enjoy a reputation for sturdy reliability, and there are many aftermarket and factory performance parts out there for the "Iron Duke" engine, as it was a very common mill in many four cylinder racing classes for YEARS!

The engines are plentiful and dirt cheap....making them all the more interesting as gas prices sneak up and down these days...I was kinda torn between the Vega motor and the Iron Duke myself...ended up going with the Vega just for giggles...but I'd swap in a Duke if that doesn't work out!
 
I think that history is a little screwed up. The 151 has nothing to do with the 153 Chevy motor, that is a poor assumtion made by somone. The 151 is a Pontiac designed motor with some design shared with the 301 V8.

-T
 
Off topic, but I had a 1990 Grand Am with the 2.5L that ran well, but went through alternators like crazy. I friend with Skylark 2.5L had the same experience. How about others here? I'm just curious, I don't own the car anymore...
 
Had a 87 GMC S15 with 2.5 great engine,sounded like a hand full of marbles in a tobacco can when it was started cold ,but couldn,t kill it.The rest of the truck just rotted away,as for oil it would probley run on pork lard,but to be safe any good 5w or 10w would work.
 
I always ran 10w-30 Pennzoil in my 1990 S-10 with the 2.5l. It was a nice little engine...not overly powerful, but they run a long, long time. Mine never used a drop of oil in 100,000 miles.
 
quote:

Those early motors incorporate a common small block Chevy bellhousing pattern so tranny choices are wide open!

More importantly, any vehicle with this engine ...could bolt up a SBC ..and any SBC trannie would bolt up to the bellhousing. Many 81-83 or 84 Jeep CJ that have this engine are highly sought after for just this reason.
 
Here's what one hardcore experimenter is doing with his Chevy 4 bangers. Check out his method of finding internal couples on a 4 banger crankshaft.

http://www.bacomatic.org/~dw/2.5/25.htm

Unorthodox to say the least, but it looks like he knows what he is doing with the crank.

In case it isn't obvious to all, the cut up and welded crank is to find the internal couples so balance weights can be cut out and welded to the intact crank.

His whole website is interesting. A mix of automotive strangeness and good info. All of it though provoking.
 
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