Coolant system pressure issues
 

In need of some thoughts, coolant system is preassureing up and pushing fluid into resivore. Only when it idles and I get in and accelerate over 2500rpm. The coolant is around 145degrees before taking off. I've changed thermostats thinking that was issue, not the case. I have an h&s egr delete and am wondering if it is because of that style. Had system pressure tested to verify head gasket. Just weird. Thanks.

Is the coolant not returning from the reservoir? If so, it may be a faulty radiator cap.

No it's not. I replaced the cap and no change. But if I hold my hand on there it will draw it back into system. It's weird.

if the water pump and thermostat is working properly, they can be only the head gasket. here is a simple test you can do. let the truck sit over night after running. the next morning crack the rad cap. if they are big pressure there you have a head gasket leaking.:hellox:

But the system was pressure checked, and held up fine. I guess it is possible a head gasket would allow air into the coolant, but not coolant into the cylinders. It is interesting how head gaskets fail.

the 6.7 seems to seal back at low boost. at least that is how mine started. in my opinion the best test is the morning after. if they are big pressure there if can only come from one place:hellox:

With it being a closed system wouldn't it hold some pressure? I have a 16lb now but why won't it draw the coolant back?

it will have very little pressure if the head gasket is ok. as the temp cools down so does the pressure.

Head gasket. I wouldnt run the factory gasket again. I would install studs and run the vulcan head gasket.

I went to Vulcan performance and they sell a victor gasket. Is this what you were referring to?