Questions About GM's 2.5 "Iron Duke" & 2.3 Quad 4

I'm hoping someone on here might be a mechanic and will know the answers to some of these questions. I've been searching the internet a long time trying to
learn more about these two engines but haven't found much regarding reliability.
1. I read online that older versions of the 2.5 were made of cast iron, thus the "Iron Duke" nickname. But, I also found something that said later versions of the 2.5 were changed to aluminum and were less reliable. Is that true? At what year did they change over to aluminum?
2. What were the various changes through the years in the 2.5 engine mechanically from say 1982 to 1992 in the 2.5 engines?
3. Which of those years ('82-'92) were the best ones made (most reliable, longest lasting)?
4. Also are there any reliability differences between say...a Chevy Celebrity with a 2.5, Olds Cutlass Ciera with a 2.5, Pontiac 6000 with a 2.5, Buick Century with a 2.5, etc.?
5. Also, I've heard that earlier versions of the 2.5 had problems blowing head gaskets frequently, was that ever fixed or do most of them all still do that?
6. And as long as we're on head gaskets....the 2.3 Quad 4 engine also blows lots of head gaskets from what I've heard, is there any year or type of that engine that is a GOOD one? Is there any way to make a 2.3 stop blowing head gaskets?(will having a new engine put in fix it or will the new one eventually start blowing head gaskets too?) One of my old friends had a 1988 Olds Cutlass Calais with the quad four and that thing had balls, it beat my 3.1 Lumina Euro when we raced, plus it got very good gas mileage. Ok, enough! Thanks in advance to anyone who has the answers to these questions and responds :)
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I don't know much about the 2.5, but they were always an iron block. I think they may have changed the cylinder head to aluminum at some point, though.
As far as the Quad 4, I think the later model years didn't have nearly as many head gasket problems as the earlier engines. It's probably advances in the gaskets themselves, actually - with an engine like the Quad 4 with an iron block and aluminum head, the different rates of expansion can cause problems with the gasket; it took them a while to figure out how to make the head gaskets reliable, especially on an engine like the Quad 4 that's relatively high-power.
--
Robert Hancock Saskatoon, SK, Canada
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In article

The 2.5 was always a cast iron block.

The majority of changes had to do with cylinder block strength. One big change around 1990 or 91 was the change from timing gears (gear to gear) to a timing chain and sprockets. The crankshafts were changed when DIS ignition became standard equipment. All of the changes to this engine can probably be read about at the "Babcox Publications" website, look for their "Engine Rebuilder" magazine.

The mid 80s castings from John Deere had a problem with the block casting cracking in the lifter galley area, it's almost for certain that all of these engine have already failed and have been replaced, but if you're junkyard shopping, it's something to be aware of and watch for.

No.

There was a problem with cylinder head bolts breaking, the head gasket itself was as durable as any other. head gasket failures were almost always the result of lost clamping force from cheap imported fasteners manufactured in the Pacific rim. (remember; "no one sweats the details at GM.") The effects of the block cracking problem as previously described could easily be mistaken for a blown head gasket since one symptom was coolant contaminated engine oil.

The 2.3 and its decendants are a turd engine, avoid it at all costs.
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<snip>

blows lots of head gaskets from what I've heard, is there any year or type of that engine that is a GOOD one? Is there any way to make a 2.3 stop blowing head gaskets?(will having a new engine put in fix it or will the new one eventually start blowing head gaskets too?) One of my old friends had a 1988 Olds Cutlass Calais with the quad four and that thing had balls, it beat my 3.1 Lumina Euro when we raced, plus it got very good gas mileage. Ok, enough! Thanks in advance to anyone who has the answers to these questions and responds :)

Quad 4's come in a few types. Single & Dual over head cams, 2.3 & 2.4 Liters. They are still used in Cavaliers & Sunbird (2.4L).
They don't just have head gasket problems, they also have head cracking problems. When I worked in salvage yards 70% of Quad 4 heads I pulled off were cracked. Some could only be found with a pressure test.
The majority of Quad 4's will blow the head gasket between the oil & water jackets. This results in what we call the Qaud 4 Milkshake. That being water (coolant) in the oil, and oil in the radiator.
Qaud 4 parts on average are more expensive then most other GM engine parts. A timing chain will easily cost you $145.00. The oil separator which always goes bad and sends oil vapors all over costs atleast $120 at the dealer (Napa does not carry it).
Very few people like Quad 4's that know what they are doing. Most Quad 4 owners attempt to go as long as they can before fixing problems.
If you want a good GM 4 cylinder look at the 2.0/2.2 engines. Not very many problems with the OHV versions, other then coolant hoses on the back of the block & oil filter extensions on automatics. Charles
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The 2.2s weren't that great, especially the later ones - some years had problems with coolant leaks from the head gasket, as well as piston slap problems. Aside from being a slug of an engine to drive, too..
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Define "piston slap" for me. As for head gasket leaks yes they do at times. So do 2.0's. Yet in comparison to Qaud 4's and 2.5 it's rare. Charles
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"Charles Bendig" wrote

Uh, no....the head gasket problems on the 2.0/2.2 litre engines is so bad that there are extended "secret" warranties on them. The 2.4 Quad engine has had almost "no" head gasket problems that I'm aware of. The 2.5 had problems with head bolts breaking, but rarely with the head gasket itself.
The late model Quads have actually been very trouble free. We hardly do any work to them compared to the 2.2 liter. Of course, the 2.2 is much more plentiful, so you have to factor that into the equation.
The 2.0 liter engine had a lot of piston slap complaints, and back then, the General had us replacing pistons on them frequently. Now, the General has basically decided that the phenomenon is "normal" and refuses to do much about the problem, except in the 3.1 engines. These engines don't just have a noise, they score the piston skirts quite badly on the front bank of cylinders.
Ian
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At the Dealer Auction outside of Richmond Indiana, IAA, I have seen a good number of 95 up J-cars come thru with 2.4's. The majority with either head/head gasket problems or lower end problems. The mileage on most of the vehicles there is usually over 100,000. Maybe 20 to 30% under the 100K mark.
A secret extended warrantee? Do tell I have a 2.2 Cavalier at my shop now that needs a head gasket or a head. If it's covered Ill send it to a dealer and have one less car waiting for service.
I personally have had four 2.0 J-cars. Two had motor issues. An 85 Cavalier RSwith a oil consumption issue, and a 87 Cavalier 4 door With a oil pan problem. The 85 I drove for two months, until the clutch let go. Then I sold it for parts. $50 dollar car brought $150 profit. The 87 had been driven over parking blocks. After I replaced the oil pan, I had troubles with the oil filter extension. I went thru 3 new A.C. Delco ones before the issue was taken care of. Other then that all the coolant hoses needed to be changed. That car lasted for 3 years, with a buddy of mine using it to deliver pizza's 5 days a week. After that I pick up a rusty 84 that was a 5 speed. So the 87 since it was an automatic got used for parts. After that I sold the 84 to my buddy, who had it for 4 years before trading it on on a newer car.
Personally I have had good luck with the 2.0/2.2 OHV engines. I have had a few 2.2's come in for head & head gasket work. Not as many as Quad 4's. The majority of cars I work on are 8 years old or older. So I have no way of knowing if they had a head or head gasket service at the dealership.
I have had a few loud 2.8 & 3.1's. The one in my 1998 Century is (3100) that way too. It's under 60,000. I had another 98 Century that ran a bit different. I do see some head issue with the 2.8/3.1/3.4 engine family, but not as many as need replaced.
On the 2.5's I don't bother doing head work on them. I have enough good complete 2.5 S-10 engines I usually just change them. I haven't been brought a FWD 2.5 in a few years. Charles
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"Charles Bendig" wrote

the
mark.
Let's put it this way. The original 2.3 Quads had head gasket problem right out of the chute, well within the warranty periods. We used to replace them the way we replace 3100/3400 intake gaskets. The late model 2.4 Quads do not have any gasket problems within the warranty period, and for some time after that. You obviously see way more high milers then we ever will. To me, there has been a big improvement. We have had a few Quads (2.4) with bottom end problems, which is strange, as the original ones had very few problems with the bottom end.

Depends on the year, have a dealer run the VIN and see if the "special head gasket policy" applies to that vehicle. If the vehicle is over 7 years, 160,000 kilometers it wont be covered.

had
I'd agree with you, I'd still take an OHV engine over the DOHC engines. Even with the head gasket problem, much simpler and cheaper to repair. What's a head gasket anyway....a few hours work, and she's as good as new.

(3100)
but
It's interesting, we have just started to see head gasket problems appearing on the 3100/3400 engines. Mainly the 3400 in the vans. The gaskets split just like the 2.0/2.2 head gaskets and leak externally. Usually the rear head gasket at the front corner.
Ian
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I owned a 1985 Celebrity with a 2.5 in it from 1986 to 2001. It ran great, never needed any major repairs and got good gas mileage. At 162,000 miles, it still had excellent compression in all cylinders and did not burn oil or have any noticeable blow-by. I've known numerous people with 1985 and above Celebrities and they've all gotten similar results. I think that the earlier ones had some problems but I don't knw what the problems were. If you can find my old car, go for it (it's the silver Eurosport with the crushed rear-end LOL).
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