The other day I was driving my pickup (1992 3.9) and as I was driving I could tell something wasn't quite right by the sound of the engine. I came upon a hill and it felt like it would lose power then gain it then lose it, rinse, repeat. I looked at my gauges and saw the temp gauge was pegged at "H". I put into nuetral and coasted into a parking area and noticed my water pump was leaking horribly. I let it cool off and added coolant then tried to start it and it wouldn't start the first time. I then tried again and it started but idled terribly. I drove it home and let it sit overnight hoping it would be fine after it had time to cool off. No dice. It was a hard start again and the idle was still off. Could I have warped a head or destroyed a head gasket?

 

check the oil for any moisture and look at the plugs see if they have crap on them that should tell you if did somthing to it.

 

Lots of possibilities. I have heard of head to intake gaskets blowing when it gets that hot. First I would check is for fuel and spark. Make sure you have correct fuel pressure and good spark. Use starter fluid to test for good spark.

 

I have checked all those things and the fuel is at 54psi, the spark is strong and tried adjusting the timing but still nothing. I was checking the compression on the cylinders and found on the passenger side that the (i'm not sure how the cylinders are numbered) front cyl was 60, the middle 81 and the back 92psi. I didn't get around to the driver's side because it started hailing so i'm gonna check those cylinders in the am. I'm not sure that the pressure gauge is correct but those pressures seem quite low to me. Also I'm not sure if it's because I added water to the system while it was still hot, but while it was running, it seemed like the coolant was "frothing" out of the radiator fill. Of course I'd love to have an easy fix and not have to take the head off but I know life just isn't that easy... I need to find a 5.9...

 

ok, so i checked the cylinders on the driver's side... 60, 32, 58psi (front to back). any suggestions?

 

Chrysler says that the minimum PSI on a compression test should be 100 with a 25% variation between cylinders. With those numbers you definitely have a blown head gasket. If you want to double check, with your compression tester, hook up shop air to the compression tester fitting in the cylinders and listen for leakage. If you see bubbles coming out of the radiator, you know the head gasket is blown for sure. If you hear air escaping the tailpipe, you have a burnt exhaust valve; if you hear air escaping from the throttle body, you have an intake valve not seating or burnt. If you decide to pull the heads off, make sure you check them for warpage; kinda hard to do on cast iron heads, but it can happen.

 

So i'm going to replace the head gasket today... would I be ok reusing the head bolts/studs or should i replace them?

 

They are Torque to Yield which are only to be used once. It is best to get new ones.

 

If you said the water pump was leaking when your shut it down... I would also look to re-place that as well.

 

MedMan, being you are having to pull the head, pull the other side too and do the job right. Take the heads to the auto machine shop and let them square, clean, replace the valve components, match the seats. You will not regret it. It'll run like a new one. While the head work is being done, as suggested remove the water pump, replace the radiator, all rubber. You will be time, $$$$$s ahead in the long run.

Don't do as the old saying goes. "WE don't have time to do it correct now BUT have time to go into it again to fix it".

Prevention; To get these high mileage or old vehicle head gaskets to last thu these horrible days of heat, when you get at a long rest stop and engine off. Lift the hood and let the building-up heat have a place to escape other than cooking your engine higher.
Another; When in hot, slow moving traffic and long at stops, get into the habit of up-shifting the trans to 'N' . This keeps the trans oil from heating the coolant that much warmer, plus saving the trans from burning its self to death too. Getting the girls to do this trick is tougher guys, so work on it.

An open request; AnyOne, send us rain and feed for our life-stock here in Texas, especially you kind ones in Iraq, Afghanistan, Haiti, and all other countries sucking on the tit since '50.