1997 850 glt leaking radiator cap

ezliving4ume · Post by **ezliving4ume** » 11 Apr 2014, 07:32

Well guys I've been busy on my 850 glt. New transmission, new pcv valve kit and a new radiator all done at the same time this spring.

I need some idea's as to why the radiator cap now leaks badly under pressure. When I run the car with out the cap on it bubbles and spurts anti freeze out of the coolant box, then the fan kicks on and all of my anti-freeze is gone out of the coolant box. The fan turns off and out comes all the anti-freeze I poured in when the fan turned on.

Or maybe I'm not filling the system correctly or ? I need a new cap

Post by **cn90** » 11 Apr 2014, 08:12

The cause is either:

1. Bad cap

2. Blown head gasket.

Try another cap first.

ezliving4ume · Post by **ezliving4ume** » 11 Apr 2014, 08:43

No smoke out the tail pipe, no water in the oil and no oil in the water. Wouldn't that rule out a bad head gasket?

I was just told by a co-worker that the heat must be on and the fan must be on in order to correctly fill the coolant system, yes, no maybe?

Post by **tryingbe** » 11 Apr 2014, 09:53

Change the radiator cap. The coolant system is suppose to be pressurized to 12-16psi, without the cap, the coolant is going to boil and get it.

ezliving4ume · Post by **ezliving4ume** » 11 Apr 2014, 10:13

i have a new cap in my hands now!

Post by **polskamafia mjl** » 11 Apr 2014, 20:05

ezliving4ume wrote:No smoke out the tail pipe, no water in the oil and no oil in the water. Wouldn't that rule out a bad head gasket?

Usually yes but not always.

ezliving4ume wrote:I was just told by a co-worker that the heat must be on and the fan must be on in order to correctly fill the coolant system, yes, no maybe?

Yes.

Post by **Ozark Lee** » 11 Apr 2014, 21:12

If you had a gray colored cap they all tend to crack and leak. Replace it with one of the blueish green caps and it will then last pretty much forever.

...Lee

Post by **MoVolvos** » 11 Apr 2014, 21:20

_

May have air in the system as you indicated a new Radiator. There could be possibility of a bad Expansion Tank also. They warp as they get old and the Cap will not seal well. This was the case for my car. A new Tank took care of the constant seepage around the Cap.

Blessings,
BKM
_

Post by **rspi** » 12 Apr 2014, 03:36

You should never run these cars with the coolant reservoir cap off. The system is designed to run under pressure. You fill the system when the car is cold.

Had gasket leaks actually have 3 options; oil in coolant, coolant in oil and combustion air in coolant (no fluid mixing).

If you have the "proper" thermostat with the bleeder pin in it, these systems fill very well. As you add coolant to the bottle, air bleeds through that pin and the system almost fills totally up. Drive a day and top it off the next day, maybe about 18 oz.

Post by **rspi** » 12 Apr 2014, 03:55

Go to 5:45 in this video.