Doing a cooling system pressure test today -- any advice for me?

[Mike Rogers]

Hi guys,

My shiny new Mityvac 4520 is coming in the mail today and I plan to use it to diagnose a coolant leak that the local indy ( whom I don't trust anymore -- long story, German Car Specialists Bellevue,wa ) hasn't been able to diagnose.

http://store.yahoo.com/sjdiscounttools/mit4520.html

Any tips for using this tool to diagnose the problem.

Here's what I've done so far without the tool and some background:

1) Goes from full / cold line to "Low coolant warning" in 7 days now
2) Just did an oil change, the oil looked fine, do see a "fudge" substance on the cap, but definitely not milk -- so I think I'm ok there with headgasket. ( Switched to Mobil 1 0w40 on saturday just to make my baby feel better )
3) Headgasket replaced 10K ago
4) Thermo replaced a couple months ago ( was stuck open), return hose system to expansion tank replaced, expansion tank replaced ( crack in it ), upper radiator hose, lower radiator hose, bypass hose replaced.
5) All clamps tightened.
6) Aux heater pump / hoses visually inspected -- look good and pump appears to run.
7) Newer cap ( 10k or so )

Car lost coolant prior to headgasket change and still loses coolant although the loss seems to have accelerated a bit. Probably doubled last 3000 miles or so.

No coolant on the driveway, no stains anywhere on hoses, etc.

Thanks for your help.

/\/\ike

[Unregistered]

Oops sorry -- 1991 535i.


Hi guys,

My shiny new Mityvac 4520 is coming in the mail today and I plan to use it to diagnose a coolant leak that the local indy ( whom I don't trust anymore -- long story, German Car Specialists Bellevue,wa ) hasn't been able to diagnose.

http://store.yahoo.com/sjdiscounttools/mit4520.html

Any tips for using this tool to diagnose the problem.

Here's what I've done so far without the tool and some background:

1) Goes from full / cold line to "Low coolant warning" in 7 days now
2) Just did an oil change, the oil looked fine, do see a "fudge" substance on the cap, but definitely not milk -- so I think I'm ok there with headgasket. ( Switched to Mobil 1 0w40 on saturday just to make my baby feel better )
3) Headgasket replaced 10K ago
4) Thermo replaced a couple months ago ( was stuck open), return hose system to expansion tank replaced, expansion tank replaced ( crack in it ), upper radiator hose, lower radiator hose, bypass hose replaced.
5) All clamps tightened.
6) Aux heater pump / hoses visually inspected -- look good and pump appears to run.
7) Newer cap ( 10k or so )

Car lost coolant prior to headgasket change and still loses coolant although the loss seems to have accelerated a bit. Probably doubled last 3000 miles or so.

No coolant on the driveway, no stains anywhere on hoses, etc.

Thanks for your help.

/\/\ike

[Karl]

You got a new cap and gasket with the expansion tank, right? If it's not holding pressure, water can boil out of the coolant, and the steam won't show much of a leak trace.

[Mike Rogers]

When they car is cold I can squish the upper hose and make the level go up/down -- swoosh/swoosh. When the car is hot, there is more pressure on the hose when I squeeze, but I can still affect the level in the expansion tank. Is this normal? If it were really under big time pressure, this wouldn't be the case, right? ( damn those hoses are hot... )

[ryan roopnarine]

i don't know specifics about the mityvac you purchased, but i have a feeling that you will need a bmw adaptor for it to fit on your car.

[Bill R.]

been thinking about buying their conversion kit to convert my stant pressure tester over to that universal setup...






i don't know specifics about the mityvac you purchased, but i have a feeling that you will need a bmw adaptor for it to fit on your car.

[ryan roopnarine]

guess i stand corrected.....here's mityvac's page on the universal dealie

http://www.mityvac.com/kits.html#universalradiatoradapter

my pressure tester currently consists of a bmw cap with a pressure oriface epoxied into place, though i can't find it, which means im going to have to make another one some time.

[Bill R.]

You can drain the cooling system, or most of it anyway and hook up your pressure tester then pump up the system, you can then pull all the spark plugs and stick a rubber hose into the plug holes and listen for a hissing sound from pressure escaping, then you can listen all over the cooling system for the same, or you can pressurize it with the coolant full but if you do so I would still advise you to pull all the spark plugs and then crank it over briefly with the plugs out after you do the pressure test, that way if you have a head gasket leak into the combustion chamber, even if it gets some coolant into the cylinder when you crank it over it will push it out the
plug hole instead of hydro locking the motor...
But with it pressurized with the coolant in the engine look for leaks in unusual places such as the seam between the radiator tanks and the center core, the auxillary pump, look at the a/c condensate drain to see if the heater core is leaking and draining out there... etc... Then when your cold test is done, release the pressure and start the engine up with the pressure tester still on the car... rev the engine up a couple of times while watching the pressure tester.... should be at zero , if the pressure jumps up some each time you rev the engine ,(just briefly up to 3K rpm and then let it back down) then its likely that you have a bad head gasket... Don't let the pressure build up much before shutting the car off, then do the same pressure test you did cold with the engine warm.... Sometimes things leak when cold that don't when hot and vice-versa , so pressure test it cold and warm...







Hi guys,

My shiny new Mityvac 4520 is coming in the mail today and I plan to use it to diagnose a coolant leak that the local indy ( whom I don't trust anymore -- long story, German Car Specialists Bellevue,wa ) hasn't been able to diagnose.

http://store.yahoo.com/sjdiscounttools/mit4520.html

Any tips for using this tool to diagnose the problem.

Here's what I've done so far without the tool and some background:

1) Goes from full / cold line to "Low coolant warning" in 7 days now
2) Just did an oil change, the oil looked fine, do see a "fudge" substance on the cap, but definitely not milk -- so I think I'm ok there with headgasket. ( Switched to Mobil 1 0w40 on saturday just to make my baby feel better )
3) Headgasket replaced 10K ago
4) Thermo replaced a couple months ago ( was stuck open), return hose system to expansion tank replaced, expansion tank replaced ( crack in it ), upper radiator hose, lower radiator hose, bypass hose replaced.
5) All clamps tightened.
6) Aux heater pump / hoses visually inspected -- look good and pump appears to run.
7) Newer cap ( 10k or so )

Car lost coolant prior to headgasket change and still loses coolant although the loss seems to have accelerated a bit. Probably doubled last 3000 miles or so.

No coolant on the driveway, no stains anywhere on hoses, etc.

Thanks for your help.

/\/\ike

[Mike Rogers]

The substance on my cap is best described as caramel in color, thicker than oil, but definitely not white.....is this something I should be concerned about?

Thanks.

/\/\ike

[Mike Rogers]

Does this look like a leaking head gasket to you guys?

http://home.comcast.net/~rugrats96/cap1.JPG

http://home.comcast.net/~rugrats96/cap2.JPG

I drive 30 miles to from work so the car is getting up to temp.

Thanks -- and pray for me....

/\/\ike

[Martin in Bellevue]

I'll be back in town next week, when I'd be glad to try a few disgnosis steps.

With the compression gauge, we could check for combustion chamber leaks to the coolant circuit. The compression gauge is showing to be a very useful, & new tool for me. I'm curious about the range of m30 compression number, as the range taken on my car recently seemed high, at 192 - 205psi, cold & dry with the throttle open.

I'd expect to see coolant loss from the reservoir tank, or any of the myriad coolant hoses on these things. Jeff had a tank leak on his 535.

I'm in Bridle Trails; Jeff is a bit south of here. Erick is around, with some head gasket experience. I'm convinced it is too easy to say bad head gasket on these m30's.

[Mike Rogers]

Did you see the pics of the cap? Mind pulling yours to see what it looks like?

Thanks


/\/\ike


I'll be back in town next week, when I'd be glad to try a few disgnosis steps.

With the compression gauge, we could check for combustion chamber leaks to the coolant circuit. The compression gauge is showing to be a very useful, & new tool for me. I'm curious about the range of m30 compression number, as the range taken on my car recently seemed high, at 192 - 205psi, cold & dry with the throttle open.

I'd expect to see coolant loss from the reservoir tank, or any of the myriad coolant hoses on these things. Jeff had a tank leak on his 535.

I'm in Bridle Trails; Jeff is a bit south of here. Erick is around, with some head gasket experience. I'm convinced it is too easy to say bad head gasket on these m30's.

[Martin in Bellevue]

The cap could have the foamy crap from who knows where. The valve cover could be pulled for more insight to the residue. There are many things to look at.

I'd like to try the compression gauge & visual inspection first.



Did you see the pics of the cap? Mind pulling yours to see what it looks like?

Thanks


/\/\ike