Author Topic: How much pressure should be in cooling system? (Read 1864 times)

rabbit_diesel · « **on:** October 11, 2007, 09:33:27 pm »

How much pressure is supposed to accumulate in a 1.6 IDI diesel engine after running it about 1-2 minutes? Is the coolant cap supposed to release any pressure. I'm just wondering if its not the head gasket :shock: . I put a brand new one in with new head bolts and checked surfaces. This car always had this these same symptoms and I don't know if it is supposed to build up that much pressure or not. please let me know. Thanks, John

jtanguay · « **Reply #1 on:** October 11, 2007, 10:04:44 pm »

how much pressure are we talking here? after IDLING for 1-2 minutes? or driving? at normal operating temp the coolant should have something like 10-15 psi or so.

is your engine a turbo diesel or no? if it is turbo then it could be the oil cooler, but if its not, then looks like your head or even worse, block, could be cracked.

saurkraut · « **Reply #2 on:** October 12, 2007, 08:26:23 am »

Warm the engine up fully with out the cap on.

Put the cap on after its warmed up.

If it builds pressure then, you have a combustion leak.

Could be another blown head gasket or a crack near a prechamber. Thats a typical area for a crack in the head from not warming up the engine properly befor applying full throttle, (or running too much propane, as Jake Russle once found out.)

A leaky oil warmer will not build significant pressure in the cooling system with out disgorging the contents of the oilpan into the cooling system.

madmedix · « **Reply #3 on:** October 16, 2007, 08:44:24 pm »

Perfect timing for this thread. The 90 Jetta TD I picked up has black crap in the expansion tank...and what looks like someone tapped in some cigarette ashes into the coolant...soot, really. Not a lot, just a tad, and not globules of oil like when the gasket went on my gasser Chev V6. I'll try Sauerkraut's idea with the cap off. I replaced the expansion tank with a clean one and changed out the oil cooler just in case. The aftermarket hoses that run from that cooler to the pipe aren't angled quite right, but it'll have to do.
BTW, the meathead engineer who designed the water pump/power steering pump obstruction from just neatly preventing proper access to clamp the coolant hoses shouldn't be allowed to reproduce. :x
Cheers,

jtanguay · « **Reply #4 on:** October 17, 2007, 12:35:02 am »

Quote from: "madmedix"

BTW, the meathead engineer who designed the water pump/power steering pump obstruction from just neatly preventing proper access to clamp the coolant hoses shouldn't be allowed to reproduce. :x
Cheers,

hehe... well the cars were originally not designed with power steering in mind. personally I want to change to mechanical steering. had it in my '86 jetta TD and that thing was easy to turn. anyone who whine's about no power steering is a wimp! down with power steering!! (unless you drive a big honkin suv :roll: )

madmedix · « **Reply #5 on:** October 17, 2007, 07:44:44 pm »

Absolutely. The way the power steering on this girl behaves it was obviously an afterthought. My old '92 was armstrong steering and it was beautiful.

Andy