Oil in Coolant - other sources?

I've got a 1998 with 2.7l 3rzfe.

I had my harmonic balancer go bad, so I replaced it. While doing so I found a considerable amount of oil in my coolant while I was draining the radiator (I removed it to get better access to the crankshaft pulley bolt). Nothing wrong with the oil inside the head at visible inspection, so I assume no coolant in the oil.

I inspected the engine and found oil leaks at the valve cover and head gasket.

I needed to drive the truck for a while until I fixed it, and during the next week my crackshaft bolt came loose while driving. My oil light and alternator light came on followed by my radiator blowing a hole in the top plastic reservoir. No good. I assume when the harmonic balancer came loose the water pump pulley lost tension and the coolant increased in pressure and some how blew the radiator... Alternator light came on for the same reason. This happened maybe 10 minutes into the drive, I assume right as the thermostat opened. I don't believe it overheated.



Back in the garage and I tightened down the crankshaft bolt with blue loctight, and this time removed the starter and jammed the fly wheel while using a torque wrench to lock down the crankshaft pulley bolt, so that issue should be fixed now.

I took this time to install a new radiator and took off the head and replaced the head gasket. It was a lot more work then I thought it would be with the camshafts needing to be removed before getting to the head bolts, and I was surprised when I got to the head gasket that there werr no glaring failures. There must have been at least a little failure somewhere with the oil leaking though. Sorry I don't have pictures of that part of the block or the old head gasket.







The intake manifold had considerable black oily build up which I cleaned out. I was under the impression that the cylinder was burning oil due to the gasket, but now I'm unsure if it's not a piston ring... The EGR valve must have been bringing in that gunky crap into the intake.

To top it off, the valve cover was being tightened down and my manual had listed 15 foot pounds as torque (which is way too much I gather from other posts)... I sheared off the bolt closest to the corner bolt, and when that happened I cracked the corner of the valve cover. I just ordered the new valve cover it will be tightened to snug plus 90 degrees to avoid that issue again...



In the mean time, could there be another source of oil leaking into the coolant besides the head gasket? Mind you there was about a quart of oil that was drained out of the radiator mixed with coolant. I've never had over heating problems... So if the block was cracked it would be kind of amazing to me.

I don't have it put all back together yet, have to wait on that valve cover to ship. I'm hoping it will all be good after the coolant flushes, but in case that new head gasket doesn't fix it, is there anything else that could cause that much oil in the coolant? Keeping in mind I've not had over heating issues...

 

5spd or auto?

 

don't overlook the radiator oil line for the tranny if you have one, check the tranny fluid for water

 

It's an automatic 4x4 regular cab with 3rz fe 2.7l. I'll check the tranny fluid here when I get a chance... It's possible I guess that the original radiator failed to separate the coolant from tranny... That's a good place to start. I'll have access to the truck Monday (tomorrow)

 

Did you get the head checked out at a machine shop?

 

It probably would have been a good idea to do that, but I didn't for a few reasons. 1) I've not had overheating issues. 2) If the head is screwed my financial ability to repair it is currently lacking. 3) the machinist square showed a flat surface on the head, with no obvious deviations

I'm hopeful that it was just the head gasket, but won't be able to prove it until I get the new valve cover later this week.

I'll double check the transmission fluid in the mean time.