When removing cap there is some pressure released,this after setting overnite.If the coolant system is getting the extra pressure from say an injector sleeve or headgasket why does it not bleed back to the source after cooling down?Is there any way the turbo could put extra pressure into the system?I have had coolant loss but not real significant,4 oz. in 4,000 miles.Have found no external leaks,nothing in oil or out the exhaust with consistant coolant temps. Jim

Mine went along for a year without anything major happening (see my other posts). Then all of a sudden it started blowing coolant. It was a head gasket. The reason the pressure does not leak back down is when a cylinder fires, the pressure goes to some high value, say 1,000 psi just for talking purposes. This forces gasses into the cooling system, just a little at first. When the pressure builds above 15 psi, the radiator cap releases the excess pressure. When you shut down, you have 15 psi on the system. This is not enough pressure to force coolant back through the very small hole in the gasket into a cylinder so the system stays pressurized.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

Either injector sleeve/sleeves or headgasket. Symptoms are pretty straight forward. I had the same symtoms. It was headgasket.

Get a cumbustion leak detector if you want to confirm yourself. Eastwood sells them for about $35.

Yellow = positive for cumbustion in coolant....

http://www.getdieselpower.com/my01dmax_files/combustion_leak/color_compare.jpg

Hey Hoot, does Eastwood sell the detector on the web? Jim

Hey Hoot, does Eastwood sell the detector on the web? Jim


Not HOOT but,Yes reasonably priced too.



How much pressure just a quick pssssst like opening a beer,or a gurgle?

Just a psssst like a Miller can. Jim

Normal in my opinion just a vacuum seal break sucking in ;)

Just a psssst like a Miller can. Jim

PM me your address.... I'll send you my kit. It's still got plenty of juice left.

When I opened my cap, even when cold, there was a big gurgle and coolant spewed. Definately pressurized.

Another symtom was intermittant cold heater air and engine temp drop.

I am thinking there was a vacumn in the tank,the coolant level rose just a bit.Never seen a girgle which I would suspect would be trapped air being released.Also looks as if no fluid has ever come out of overflow tube.The temp gauge does not move around alot and the heater seems just fine.Am going to slip a ballon over the overflow tube,if it blows off I will know the system has vented off excess pressure though when checking coolant level with hot motor the level is always about midway between cold mark and overflow.Now I wonder what would cause the vacumn to build up in the coolant tank!Going to really keep an eye on things here,will keep a post on this and thanks guys. Jim