1993, 2.3, RWD, 270,000 miles

I have low compression in two cylinders (90 and 100). No real issue in operation except on startup or trying to get over 65 on the highway. I also have an oil pan gasket leak.

Question/recommendation: Should I replace the engine or just pull the engine to replace the gasket and do a valve job? I can get a junkyard engine is $500 with about 150k miles.

I don't have a cherry picker or engine stand to do the work myself so would need to source this out to a local mechanic. Estimate is still TBD. Waiting on some guidance here before calling around.

Thanks, Adam

 

1993 2.3l engine can ONLY be replaced with a 1989 to 1994 2.3l engine, just an FYI, 1995-1997 can not be made to work, different crank sensor setup

Low compression is leaking/burnt exhaust valves 98% of the time so just rebuilding the head should fix it up
What were the compression numbers on other 2 cylinders?

90 or 100psi would mean misfires, expected compression on a 1993 2.3l would be about 150
When any cylinder gets down below 120psi, that cylinder will start to misfire

2.3l also uses a timing belt that needs to be changed every 80k miles, and that belt or its tensioner can stretch or loosen up which throws off Valve/Piston timing and that lowers over all compression
The lower the overall compression the lower the overall power

At 270k miles you still have at least another 100k miles left on lower end, rings and bearings, so I would pull the head first and see whats what

If you have the compression gauge you can test for leaking valves by redoing the DRY test, then add some oil to the Low cylinder(teaspoon) and do WET test, result WILL go up, but how far it goes up tells you if it leaking rings, or leaking valves
If it goes up equal to or above "normal" cylinders, then Rings are the issue
If it doesn't then leaking Valves

 

What were the compression numbers on other 2 cylinders?
#1 - 95
#2 - 120
#3 - 100
#4 - 130

The timing belt and tensioner were replaced about 6 moths ago.

Thanks for the help.

 

Gauge is reading low, which is fine for this type of test, and yes 1 and 3 are more than 10% lower than average of the other 2(125psi) so an issue
I would do WET test on all 4 cylinders, since overall compression is low
If WET test gets 2 and 4 up to 150psi area then rings are suspect so not timing belt issue and engine hoist would be needed to swap engines

If gauge tests OK on another engine(most engines test at 150+psi) then your belt timing is off, but there would still be the issue with 1 and 3

Redoing the head would be worth while in my opinion, doesn't help with oil pan but can be done without engine hoist

 

@RonD is there a how to (other than YouTube) where I can find how to redo the head? Also, how would I get the oil pan off without a hoist?

Thanks,

 

A machine shop re-builds the head, a valve job, you just take it off and put it back on

No, not really any way
Inside the oil pan is the oil pick up tube for the oil pump, its at the lowest point inside the pan
so even after all the bolts are out the pan has to drop down enough for the front part of the pan to be pulled out passed the oil pick up

You "might" be able to loose/remove motor mount bolts, and jack up engine high enough(transmission hits firewall), to lower the pan enough to remove old gasket and clean the surfaces, then install new gasket and seal it
If there is a big oil leak, at the rear, then its the rear main seal, not the oil pan gasket, transmission needs to come off to fix that

Oil pan gasket leak is a slow drip now and then, there is no pressure inside an oil pan, just oil spraying around from connecting rods, and gasket is higher than oil level so oil can't just "leak out" like it can at the valve cover

 

Well...I don't use the truck as a daily driver. There is defiantly an oil leak on the ground when it sits. I could have installed the rear main seal incorrectly, but I doubt it. Is there another area under and/or around the engine I should inspect?

Calling around to local shops, it is cheaper to buy a different truck than have them do the labor.

 

Would one of those engine lift bars work? The ones that use the engine bay frame as the bracing. Just enough to get it high enough to curse and finagle with. Never used one personally.