Am I paranoid or is it my head gasket?

so reading all these head gasket failures on 2005 Tacoma's got me checking mine. Here's what got me investigating. My CEL came on a couple times, once or twice while starting it wound over slightly longer than normal. Idles fine, no overheating.

One concern I have is if I start truck with radiator cap off the coolant will slowly push up and overflow. However there are no bubbles at all, and all cases I've seen with bad head gaskets have bubbles in the coolant. Is a coolant system pressurized this way? I'm hoping its normal to have pressure in the coolant system as I don't want to spend thousands on dollars on replacing my head gasket.

Anyone have any insight on whether this pressure, rising coolant with cap off (no bubbles!) is normal?

I'll have mechanic hook up a code reader Monday when it goes in for pinion bearing replacement. Just looking to ease my mind in the meantime

Thanks.

 

what happens if you pull the rad cap off when the truck is fully warm (not over heated) and make sure to undo it slowly with a rag over the top. The coolant should stay inside.

Id bet the slowly push up and overflow you are seeing is a result of the tstat being closed when cold.


Are you experiencing any coolant loss?

 

No coolant loss, overflow tank hasn't moved in last 1000km (how long I've owned it)

Haven't tried opening rad cap with engine up to operating temp yet.

I just got truck back from frame replacement last Friday evening, so it has fresh Toyota coolant.