Cooling system clogged?

[yanga001]

Systems pressurize after a run so what may be happening is a leak through a gasket or at a connector or crack. This is why mechanics perform coolant pressure tests to see if the system is capable of holding pressure. Our systems differ from hondas/toyotas which utilize an expansion tank to relieve pressure as it is isolated through the radiator cap. Our expansion tanks remain pressurized which is why you cannot remove the cap when the car is running.

My partners Acura RDX does this as i suspect it has a leak near an oring to the turbo (same turbo conicidentally as our volvos). Car does not leak when left alone but does leak a bit when the system is pressurized. When the car is running the engine will be hot and may cause the fluid to evaporate instantly so it may "leak" but leak as steam.

post a picture if you can

[hiroku]

Thank you for your replies.

Yes, the block was flushed as well without the thermostat.

Will make sure to check that engine mount when I next have the car on the lift. That said, the leak is on the driver's side of the radiator, near the lower hose.

I have since driven the car twice and haven't noticed any coolant loss. Admittedly it's been relatively short drives mostly at low speed, but plenty enough for the engine to reach operating temperature.
Wouldn't usually consider stop-gap solutions, but at this point it seems to be such a small and intermittent leak I could try using some RTV sealant around the endtank seam?

[hiroku]

post a picture if you can

I have this one from a couple days ago when I managed to replicate the leak.
You can see it slightly wet from the area where it drips (when it does drip).

[scot850]

That is less likely to be the engine mount. But worth checking anyway. It looks like the seal is failing. If it is just at the bottom there, is it worth trying to squeeze the crimps sightly?

Neil.

[hiroku]

So I did the cheap test for CO2 in the coolant, and the results are a bit inconclusive.

I did it with the engine warm, between around 84 and 96 degrees Celsius, for a duration of about 5 minutes. I turned the engine off as the coolant level was rising too much in the reservoir and was about to overflow into the testing tube.

The fluid did change color a little bit, as visible from the pictures. However, on cars with a very bad head gasket, I've seen it turn bright yellow within a couple of minutes...

Could it be that I have a very small leak? I believe it's more likely that the slight change of colour was simply due to the fluid reacting to the CO2 in the air that was in the reservoir and was pushed through the testing fluid as the level increased.

Opinons?


Start of the test:


After around 5 minutes:

[kcodyjr]

I would call that a hot reading, though, not bad just yet. It's in no way severe enough to cause such overpressure that coolant seals break. There may be an engine tear-down in the future, but, it's not related to your radiator leak.

I would still plan to do a dry and wet compression test, to ascertain the condition of the rings.

I trust that if there was any coolant and oil mixing, you'd have noticed it in one or the other.

I'm leaning toward thinking this is just a radiator failure. Try crimping it down with the channel lock pliers and see what happens.

[hiroku]

I would agree with everything you have said.

Compression tests are definitely planned for the near future with new plugs ready to go in. Just time is the main limiting factor right now.

No oil and coolant mix whatsoever. The oil still looks clean and the level hasn't moved in the dipstick.

Will try cheap temporary radiator fixes for now, replace the more accessible rubber hoses, and do another flush.

Thanks for the input.

[kcodyjr]

Will try cheap temporary radiator fixes for now, replace the more accessible rubber hoses, and do another flush.

Don't use radiator stop-leak unless you're totally okay with replacing the heater core as well as the radiator, and risking it plugging up God knows where in the block and head. Could easily mean replacing the thermostat.

I'd just keep topping it up until I replaced it.

[hiroku]

Definitely not using any stop-leak products! The cheap fixes I was referring to are more along the lines of trying to physically cover the radiator leak with something like JB Weld, or squeeze the crimps on the endtank together, as has been suggested in this thread.

[hiroku]

Interesting development today.

Parked after a longer drive and could see coolant dripping into the ground, but not from the usual spot on the radiator. Found the expansion reservoir full to the brim, and a steady stream of coolant overflowing from around the cap.

At this point I plugged in the ELM and read the atual coolant temperature to be 103 degrees, so I don't think there was any overheating involved?

After a few minutes it eventually released the pressure and the level dropped to just below the minimum mark. I noticed the cap was still making intermittent "pshhh" sounds, so I opened it slowly, and I could hear a faint "click" sound as if the little valve on the cap had slammed shut.

Wondering whether the radiator cap is bad, and this could be causing the excess pressure in the system that is causing all hoses and radiators to fail? Currently installed is the Nissens cap that came with the new expansion tank I replaced a couple months ago. I wouldn't expect it to be faulty straight out of the box, so unfortunately the head gasket theory seems to be gaining more traction now...

Thoughts and opinions are appreciated.

Thanks!