Hi everyone, just a quick question to those who know the 4.2L. I had my plow hooked up, drove down the highway for 20min got off. two traffic lights and check guages chime rang. Looked and notice the temp gauge pegged at 260. Shut her down coasted and refired so I could pull into a gas station then shut it down again. Opened the hood to check things out. Coolant was bubbling out of the overflow. Started the engine and turned on high heat and the temp fell rather quickly back to 210. At first I thought the plow blocked the air flow and caused it to over heat. But the drive back home was fine. (35min). next day I find the tell tail yellowish crap under the oil fill cap. I wipe it off and check again every 24 hours. The engine runs fine, no issues. but I have been checking every 24 hours and wiping the yellow crap off. 3-4 times so far. Can't tell if the coolant level has changed. No sign of yellow crap on the dip stick.
What are your thoughts? blown head gasket? cracked/warped head? How durable are these engines to overheating? i'm sure I'm not the only one who has overheated one of these. A local mechanic stated the yellow crap is somewhat normal for GM engines, although I've never seen it on my 4.2 before. He said the 4.2L is nearly bullet proof and not to worry. What do you think?
I plan to monitor for a few more days then drain the oil into a clear container to see if there is any water in it.
1 day after it coded P1484. Found the SB for it so I'll check out the condition of the fan clutch harness.
Been driving for a couple of days and it trys to over heat only when the plow is on and the roads are wet. If they are dry then the fan operates fine.
I pulled over on the way home from work today due to the temp rising over 220-240 and the fan was spinning slowly. after tapping on the shroud, core support and other areas the fan turned on to the high speed. Must be the harness.
anyway thanks in advance for any suggestions about possible source of the water in the oil. Maybe the yellow crap on the oil fill cap is normal? I hope. Let me know if anyone has seen this on theirs. At least it will put my mind at ease.