Don't think is a headgasket

robjames · 10-14-2009, 11:07 PM

so far the symptoms of the truck are those that are somewhat consistant of other trucks that have had blown headgaskets. so far i have pressure tested the system and have down a block test that checks for combustion gasses in the coolant and both test show no sign of a blown headgasket.

so here are the symptoms, after a cold start and letting the engine warm up a bit, i begin to drive. the temperature gauge shows that it gets roughly twenty degrees below operating temperature then it cools off to where it doesnt even register on the truck temperature gauge.during this time period the heater will not blow warm air. it will do this for roughly ten minutes, then the temperature gauge shoots up to as much as 240 degrees, stays there for a couple seconds then rapidly cools down too around 190. when it cools down to 190 it loses coolants out the over flow hose, enough to where the low coolant light comes on. this all happens with in a matter of less then twenty seconds. it will only do that after the engine is cooled completely down and it will only do it after the one during the warmup process. i have driven it up to three hours afterwards with out it getting hot or any other symptoms. i have replace one of the thermostats, the NAPA dealer says they cannot order the other but after testing it in a pan in water on the stove it seems tow work just fine. right now im at a loss and would apprecite any feedback.

kansas · 10-15-2009, 12:26 AM

Check your cap.

DuraTitus · 10-15-2009, 05:23 AM

Quote:

Originally Posted by kansas

Check your cap.

What cap?

It seems like a bad coolant thermostat that is sticking, but If you checked that out you have me stumped.

mijdirtyjeep · 10-15-2009, 05:30 AM

Did you bleed the air out of the system when you installed the new Thermostats Bleeder screw is on top of the Thermostat Housing"? The cap that kansas is talking about is on the overflow bottle, and gets dirty. Just remove it and soak it in hot soapy water, clean and put back on. As far as your gauge, could just be a bad gauge cluster, or sending unit. You need to have it data logged when it is bouncing so you know the truck temp.

robjames · 10-15-2009, 07:03 AM

i bought a new cap and put it on. i also have bleed the system a couple times using the screw on top of the thermostat housing. i think because of the rapid changing of eat there is some sort of air bubble, so im going to put a "T" adaptor ina heater core line and fill up the system again and hopefully eliminate anybubbles

robjames · 11-03-2009, 10:59 AM

so i changed the water pump cause it had a pretty small leak out of the weep hole. (that was a fun job) still having the same problem. i also pressure tested and block tested it again, no signs of head gasket. still searching for help, i bought the 400 dollar service manual for the truck. i noticed that on my truck (i bought it used) that there is a valve on on a pipe just behind the thermostat housing that goes directly to the turbo and it and some kind of sealent around it, and this isnt showed in the service manuals. so i took it off and cleaned it and pressure tested with out any more sealent and it works fine. know anything about that? or just about my problem in general anything would be appreciated!

robjames · 11-09-2009, 06:17 PM

okay so i completely took the thermostats out and it eliminated the crazy temperature readings, but im stilll loosing some anitfreeze through the over flow hose. i can watch the bubblecome up through the surge tank, but when i put the block testing dye kit on it to test it the dye will not change color. anybody have any other ideas why it could be pressurizing?

mijdirtyjeep · 11-09-2009, 06:26 PM

Diesel exhaust does not always turn the dye a different color. Sounding more and more like a head gasket. Let the truck sit overnight, and go out in the morning and try and squeeze the upper radiator hose. If it is hard, it is time to replace head gaskets.

mijdirtyjeep · 11-09-2009, 06:27 PM

What year is the truck???

**TYREBOYZ_DEMAXIN** · 11-10-2009, 06:37 AM

i hate to say it but it sounds like HGs..i know you did several tests but it sounds just like the last 2 diesels i changed HGs on! thats realy the only way it could be pressurized like that!