ddwyer

94 4x4 DLX
2.4l 22RE

I replaced the engine in early spring 08 with a used engine off Craigslist (100k miles on it). I was a bonehead and didn't mix the coolant right, so one cold morning I iced up the t-stat and overheated the engine. I pulled over right away, but the gauge pegged.

Fast forward two years. This week my truck began running a little hot. I checked the coolant, found it low and topped it off. Today the truck overheated, pegging the gauge. The coolant is very low, but I see no coolant on the ground and none in the oil.

I suspect a blown head gasket, head or cracked block. How do I figure which of the three it is? Assuming it is one of the three.....

yayfortrees

I doubt the block is cracked, since you don't have coolant on the ground or in the oil. It could be either the head or the head gasket, almost impossible to say without pulling it off. (or them - is it a 2.4 or 3.0?)

I would pressure test the coolant system and radiator cap next. If all of that passes, monitor it closely and make sure it is a HG or head problem, before you go pulling everything apart.

ddwyer

It is a 2.4, so it's only one head.

This may sound funny, but even though I have replaced the engine, clutch, etc, I have never pressure checked a coolant system. How do I do this?

annoyingrob

you need a special tester to pressure check the coolant system.

If you think it's the head gasket/head, then do a compression test, and/or pull the head off.

yayfortrees

A blown head gasket or cracked head won't always show a drop in compression, so that's not entirely definitive.

Any shop should be able to pressure check your coolant system for $15 or less. It doesn't take very long, save for everything cooling off enough to safely remove the radiator cap.

I would spend a little time actually diagnosing it, rather than just start pulling the head on a hunch.

Let us know what you find.

ddwyer

I picked up a compression gauge and coolant test kit today (Advance and Autozone tool loaners). I will test both tomorrow.

BTW, I drained coolant to look at it for oil, and it's free of any oil. There wasn't much left, so with no leaks and no signs of coolant in the oil, I'm pretty sure it's head, HG or block.

yayfortrees

You'll want to fill the coolant system back up, at least most of the way, before you pressure test it.

Let us know what you find tomorrow.

ddwyer

I refilled the cooling system with water. My guess is that the mixture is about 10 to 25% coolant at this time.

I did a pressure test with the engine dead cold (30-ish degrees overnight). It held 17 psi for a half hour.

I de-pressurized the system and left the gauge in the radiator filler. I started the engine and lit it idle up to normal operating temp. The pressure increased to about 12 psi. When I revved up the engine to warm it up more, the pressure increased to about 14 psi. When I revved it at this elevated temp, the pressure dropped about 2-3 psi as I revved, and it would return to 14 psi at idle.

I then turned off the engine and pumped it up to 17 psi. It gradually dropped pressure to about 15 psi in under five minutes. It continued to drop slowly after this.

Throughout the test, water dripped from the tailpipe. I know that water is a by-product of combustion, but I would expect that once normal operating temp was reached, the water should be reduced and all vapor (no liquid).

Three questions:
1. Is the pressure drop during revving normal?
2. Is the pressure bleed-down after I turned the engine off normal?
3. Is the water generation after warm-up normal?

yayfortrees

Before I answer questions, did you test the cap? There should be an adapter to place the cap on the tester.

1. Don't really know. I've never used a pressure tester in that way. To me, the test results are inconclusive. It sounds normal to me though. The first rev probably dumped a volume of much hotter coolant from the engine into the radiator, which would increase the pressure. Since the pressure dropped when revved after that, it doesn't sound like compression gases are leaking into the cooling jackets.

2. The pressure bleed down sounds normal. These smaller motors and coolant systems cool down pretty quickly, especially if it cool outside.

3. Water continues to condense in the exhaust for a long time. At idle, with the exception of an occasional rev, the exhaust won't completely warm up for a very long time. When driving, you are holding a higher RPM, moving more hot air through the exhaust, so it finally heats up completely and stops condensing moisture.

In summary, the test so far seems good to me. Make sure you have tested the radiator cap. Once that has been tested, or if it has already, post the test results on here, and we'll go from there.

peow130

I would check the timing chain cover. If it's a high mileage engine, then the timing chain guides could have broken and the result would be the timing chain wearing a hole through the cover. Simple way to check is to pull the valve cover and inspect the guides.
If the guides are missing or broken, it's a good chance that this is your culprit.

yayfortrees

Huh? Is this the right thread for this? I mean, yeah, the 22R motor is notorious for this, but this thread is about overheating; cooling system; etc.

peow130

Yes sir.
If he's losing coolant, and overheating, then this could very well be the culprit.
He said hes suspecting a blown headgasket, but a timing cover hole could be an issue.
When a hole gets worn into the timing chain cover, it lets coolant into the engine. It could be a very small hole, so at the moment the amount of water in the oil might seem like none. But i'd still be checking it out.

ddwyer

When I replaced the engine in '08, I put in a new timing chain, cover, guides and tensioner. Besides, if the cover was leaking, I would see frothy oil, right?

I took compression measurements on cyl #1,2,3 (had a hard time getting to #4, so I passed).

warm engine, dry/wet readings:
1: 205/210
2: 165/155
3: 195/195

I used a rubber-tipped gauge with barely enough tool clearance, so the readings may be a little off. Even with the error, I think that maybe #2 is leaking at the HG or head.

Anyone have an comments on my compression and coolant system data (see msg above for cooling system data)?

swampfox

I had a turbo 22re that lost antifreeze when i drove it , but i couldn't find any signs of a leak. it turned out to be a crack in one of the exhaust ports. have you ever noticed a faint sweet smell around the tail pipe when idling ? it could be a indicator of antifreeze in the exhaust.

ddwyer

yayfortrees,

I checked the radiator cap.

Either the adapter doesn't fit well, or the cap doesn't hold pressure well. Even after wetting the gasket and holding the cap submerged in water, it wouldn't hold more than 2-3 psi.

I would love for it to be the radiator cap, but what about the cyl #2 compression readings? I know that I had the hardest time getting a good seal with the rubber-tipped gauge on #2, but I don't want to wish for the easiest solution (cap) and ignore possibly compelling data.

Maybe buy a new radiator cap and see if it overheats again?

ddwyer

swampfox,

I *think* that I have smelled sweet exhaust recently. But, since I lost and re-filled coolant a week ago, I have been kind of paranoid and maybe sweetened the exhaust in my mind. Then again, maybe my nose was right and my brain had nothing to do with it.

Is there a tracer I can put in the coolant and then look for in the exhaust gas? I know they make it for oil....

yayfortrees

Ok, so I'm assuming you're talking about a hole in the water pump, which is very close to the timing cover?

Dwyer, the only thing left to do is a leakdown test (assuming the radiator cap tested ok). Unfortunately, this is a difficult test to perform without all the right stuff. If you're ready to just pull the head to see what you find, go ahead. If you want a definite answer, have a leakdown test performed on at least the #2 cylinder.

yayfortrees

Dwyer, I would absolutely go with a new cap, and see what it does then. When you were testing the cap, where was it leaking from?

swampfox

there is probley something on the market that would cause the leak to show up . I noticed the crack after i had already pulled the motor. you should try the new cap if you are in doubt about your cap. always try the cheap and easy stuff first.

ddwyer

peow130,

I pulled the valve cover and peered down the timing chain area. Though I coudn't see well, the guides *appeared* ok. Is there any way to make a more thorough evaluation?