Oil / Coolant Saga

[krambjas]

Ok, this saga has been going on for a while, so here's the story:

Quite a while ago, my 1989 Ranger 2WD, automatic, with a 2.9L V6 developed an issue where the coolant would drain into the oil pan. I'd fill the radiator, let the truck sit, and a week later the radiator would be empty and all the coolant was in the oil pan.

So, assuming a blown gasket somewhere, I took the engine apart. I replaced every gasket in the engine: heads, intake manifold, exhaust manifold, front cover, water pump, and oil pan. It was a pain in the ass since I did everything with it all still in the truck, but I got it all apart and put it all back together. It started up on the first try and seemed to run great. A week later, all the coolant was in the oil pan again.

So I pulled the engine out of the truck, figuring I did something wrong and that it would be easier to do it right with more room. It sat for a while as I was working on other projects, but I eventually got back to it. Tore the entire engine down to the block. Cleaned everything off and looked for issues as I went about putting it back together. I replaced every gasket in the engine again, but checked for leaks as I put every part on. So I put new head gaskets on, torqued up new head bolts, plugged the coolant holes in the block, and filled the block with water. No drips or leaks. Did the same thing after I put the intake manifold on (and actually had a leak the first time I did it), and the front cover/water pump. Plugged all the tube opening in the water pump and filled the engine with water again. Nothing. No leaks at all.

So I put the engine back in the truck. Hooked everything back up. Once again, engine starts up first time. Everything seems to run great. I drive it around for a bit to make sure things work, no issues other than a needing to tighten up a couple hose clamps. Checked the radiator once more to make sure nothing was wrong and everything looked ok.

I left for work for a few days and left the truck to sit. I checked the radiator last night. Empty. Dipstick has cloudy oil and is overfilled. All the coolant is once again in the oil pan.



I give up. What wormhole have I opened up that would allow coolant to end up in the oil pan when the cooling system is not pressurized (remember, I opened the radiator to check it before letting it sit) and when all gaskets are new and were checked for leaks? I'm at a loss.

 

[dangerranger83]

Might have an internal crack that cant be fixed. Might be time to chuck that 2.9 and find another. From the sounds of it you've done everything you could to fix it but with no luck.

 

[Psychopete]

You must have the patience beyond what I could even think of.

What sucks though is that what you describe sounds like a typical problem with these engines. I went through the same thing with my '88 Ranger. I actually kept driving it that way until the bearings were toast because I really didn't know any better (I was 17 at the time).

The heads are prone to crack and it sounds like this is what has happened. It is possible to have a cracked block, but the head cracking problem seems to always be the culprit when people end up with coolant in their oil.

I worked at a shop a while ago when I was in college, and if the heads came off anything, they went to a shop on the customer's dime to be magnafluxed. But a lot of shops don't seem to know where to look (top of #1 and #6 cylinders - same cylinders since the heads are interchageable from left to right).

Not sure what would be the most practical, but Ford did produce a better head on the later models. But you have to know what to look for, and they are still prone to cracking. There are aftermarket replacements available as well that are better than either of the heads, but you'll pay for them.

FWIW

Pete

 

[krambjas]

But wouldn't a crack have shown up as at least a drip when I checked for leaks by filling the block with water? The coolant always ends up in the oil while the engine is cold and the cooling system is unpressurized, so we're talking just the weight of the coolant causing the leak.

I would think it would have to be a rather visible crack in order to empty a radiator of the over course of 4 days, all while the engine was cold.

 

[IMenriched]

Might not show up until the heat builds from running it awhile

 

[jasongind]

make sure the heads and head decks arn't warped at all. I did the same thing with my '88 2.9L. I tore it down and replaced heads and gaskets twice. The first time the number 1 cylender was cracked. Bought some remaned heads, replaced all the gaskets and head bolts and put it back together. Started and ran fine but a few days later the oil was contaminted and I had no coolent left. So i tore it back down took them to get 'fluxed and one of them was warpped. So I bought the World Industies heads put it together ran fine. About two weeks later same thing. Tore it down and check the head deck, also warrped. Thats when i said screw it, put it back together and ran it like that. I changed the oil every 1500 miles for about 6 months then sold the truck. And yes I let the buyer know about all of that lol.

 

[krambjas]

I haven't had any thing magnafluxed (which would only find cracks, not warpage), but I did check for warped heads before putting everything back together. Everything was within .005", within spec, when I measured it.

Course, I would have given up after rebuilding the thing three times. Head gaskets aren't that cheap.