1989 4Runner. This overheated on the highway, and was towed into a shop which diagnosed a leak in the radiator. Assumed blown head gasket. The truck was listed for sale as-is with coolant in the oil and I bought it. I topped up the coolant and drove it home, about 20 km's. The engine ran perfectly, no smoke, smooth idle, quiet. It did not over heat. Once I got it home I drained the oil and coolant. I then performed 3 oil changes in a row. At each oil change I would run the engine for 15 seconds (no coolant) then let it sit for a few hours, then run it for 15 seconds again. I did this about 4 times per oil change. I was attempting to flush out the coolant contaminated oil as I knew I wouldn't get to the head gasket job till this spring.






I have now pulled the head, and am trying to decide how to proceed. I can see no evidence of a head gasket failure. Both timing chain guides are broken, and the chain is wearing in to the timing cover and head. OK great, hole in timing cover, easy fix! Accept, what about the engine over heating? Coincidence that they both happened at the same time? And I have oil in the two rear intakes.

The cylinders look OK to me, there is discolouration where the rings sat for the winter (my assumption). This truck has 260K km's or 162k miles. I am wondering if anyone knows whether that crosshatching could be original?


The head looks fine to me, the valve seals are shot, crumbled to pieces when I removed the valves. The cam bearings look great, but the rear cam journal is scored.




This was supposed to be a budget head gasket job, clean and machine the head, new gasket and GTG! But obviously I will now drop the front diff and oil pan clean everything up and install new timing set. I have ordered OSK head gasket kit, Japanese timing set, water pump so far. Sending the radiator to a rad shop.

Any ideas about the oil in the intake plenum?

What about my method of flushing the coolant contaminated oil?

Should I pull the engine and re-ring re-bearing the engine? Where do I draw the line?

I am on a budget, but no time line. This is just a fun side project on what seems to be a relatively low mile well maintained truck with a clean interior. (Too bad it is an automatic transmission.)

Looking forward to any insight this site may have for me and thanks in advance!

Jonathan

 

Assumed blown head gasket? You could have done some checking about that. Compression test, leakdown test, etc. cam bearings fine but scored journal? How could that happen? Since it's a fun project, might as well go all the way and cover all angles. I don't understand the rationale behind the multiple oil changes routine. Just my $0.02.

 

Multiple oil changes was to hopefully get the coolant out of the bearings. I understand it is not good for them. Maybe its only hard on them when the engine is running? Yes, the scored cam journal is strange. I didn't bother to investigate the extant of the engine damage as I was buying it regardless, the price was 1250$ which I am pretty confident is a good deal. The truck came with many years of receipts, it was meticulously maintained. I'll update here once I get the oil pan and timing cover off. I am not afraid to pull the engine and rebuild it, but it seems silly to do so if it is in good condition. Maybe I should check the rod bearings once I get the pan off?

 

Just did a freshening up on my 22RE last year because of a head gasket leak with coolant in oil.Engine had 174,000 miles on it and still showed factory hone marks in the cylinders just like yours. I was surprised at how bad the rod bearings looked in mine.

 

Man, this is why I always beg people to do a compression and leakdown test before disassembly. And practically no one does. That info would be gold right about now.,.,.

 

So what happened is the timing chain had worn though the timing cover, allowing coolant from behind the water pump to enter the oil. The radiator had no leak. The machinist touched up the head but it was not warped. All re-assembled, new gaskets and seals, new timing cover, Aisin water pump, OSK (Japanese) timing chain, new fuel pump and filter, plugs etc. I also installed new rod bearings while I had the oil pan off. Running beautifully! Quiet and strong! (For a 22re in front of an automatic transmission )I've been driving it the last week and really enjoying it.