Gasket test results :) :)

[mar601]

I used one of the RELD test kits and the fluid stayed as blue as BB King. N I C E.
After the engine was about 208 or so I think, I revved it and coolant came through and even partially melted that test tube. So naturally the color changed, but up till I did that it was always a steady blue.

Tried to get that thermostat changed out beforehand and the screws cracked open pretty easily with the socket and a piece of conduit, but getting that one screw out I didn't want to chance it. Took the overflow hose off but still, too risky for me. Going to try Carx for that -- they have always done a good job at small things for me. Or I may try again later.

The upper hose didn't bloat as much (because that test tube vents the system?). I'll try again with the cap and will order a volvo oem part.
Want to also check my fan.

Q: How do you get that black housing off with the 2 fan plugs on it?

Q: Silly question maybe but can I drive for the time being with the cap "slightly" loosened to relieve pressure and make short trips?

Q: So if it isn't exhaust gases, what is causing the pressure and the hose to blow off? (It is absolutely secured with the oem clamp).

-- Thanks

EDIT -- Btw, there were "bubbles" coming through the tube on a regular basis. At first, maybe every 3 seconds, I'd get a "blurp" and then as it heated up, more often.

[duke1]

I used one of the RELD test kits and the fluid stayed as blue as BB King. N I C E.
After the engine was about 208 or so I think, I revved it and coolant came through and even partially melted that test tube. So naturally the color changed, but up till I did that it was always a steady blue.

Tried to get that thermostat changed out beforehand and the screws cracked open pretty easily with the socket and a piece of conduit, but getting that one screw out I didn't want to chance it. Took the overflow hose off but still, too risky for me. Going to try Carx for that -- they have always done a good job at small things for me. Or I may try again later.

The upper hose didn't bloat as much (because that test tube vents the system?). I'll try again with the cap and will order a volvo oem part.
Want to also check my fan.

Q: How do you get that black housing off with the 2 fan plugs on it?

Q: Silly question maybe but can I drive for the time being with the cap "slightly" loosened to relieve pressure and make short trips?

Q: So if it isn't exhaust gases, what is causing the pressure and the hose to blow off? (It is absolutely secured with the oem clamp).

-- Thanks

EDIT -- Btw, there were "bubbles" coming through the tube on a regular basis. At first, maybe every 3 seconds, I'd get a "blurp" and then as it heated up, more often.

has it overheated?it is my experience that on my 850se 2.5 10 valve that the test kit for checking head gasket tells lies,it said my head gasket was leaking but it is not and im unsure as to the reason for this, my guess is something to do with the pcv system and condensation in the oil but then it says the kit detects combustion residues to indicate gasket leak and so that theory sinks! either way id not trust the test kit ,
if it is as i read you still have the same thermostat then if the car has overheated this can kill the thermostat in which case it will not allow full flow of coolant and will bubble and burp and run hot also the fan may not work depending on type and location of sensor,mine took a lot of coaxing coolant around after changing rad and waterpump lots of squeezing hoses and running up to full temp then allowed to cool without the cap on coolant res,then top up and drive again and check after a few miles as it did drop a little even with zero leaks i think theres just a place air bubbles get trapped,good luck

[jmartin919]

Why is this discussion broken up into 3 different threads?

[dikidera]

I think you DO have a failed head gasket, it's just your tester must be faulty. And usually the test IS performed by revving the engine beforehand, in order for exhaust gasses to BUILD up in the coolant system.

[mar601]

my bad on the threads. they say to put in the tester, start the engine and let it come up to temperature (10 minutes or so -- 206F I think it was) and it stayed blue the whole time. anyway -- 297 bucks (wtf?) to replace thermostat at Midas 1.8 hours labor which is nonsense. will try again to replace it myself or I take it in to volvo. sorry about all my gibberish on it.

[rrres]

I just looked up RELD and it looks like a beer or wine making air lock. I used a tester from the auto parts store and it had the rubber pump that sucked air from the coolant tank. I think the results from these blue fluid testers are not always accurate. I did the blue fluid test on mine and it passed, but later found out that the car had a small head gasket leak that was letting coolant into the combustion chamber and vice versa. It's best to perform other tests to confirm. I don't know if you've done compression and leak down tests yet, but those are pretty reliable. Another test is to pressurize the cooling system and leave it pressurized all night. If the pressure drops to zero by the next day and there are no external leaks, then there might be an internal leak. Don't start the car and pull the spark plugs. Stick a borescope in each of the cylinders to see if you can see traces of coolant. After that, you can then try to start it. If it's hard to start or runs rough for the first minute or so, then all the coolant that was pushed into a cylinder is hindering combustion.