Hey guys. I'm over at the mechanics posting this post.

My family's "member" 95 Volvo 850 T5R has had a few radiator issues [the oil-coolant mixed up and created that brownish goop that clogs the whole system] last year which lead to us disabling the oil circuits in the radiator untill we can afford a new one.

The buildup of goop cracked the coolant fluid retainer so we got a new one and brought it to the mechanics for them to replace it [we don't have the tools at home to make it ourselves].

As soon as they turn the key to test it, there's a massive pressure buildup that makes water squirt everywhere from the closed lid.

Anyone has the slightest idea what might have caused this? And how to fix it? I don't even want to think in the worst case scenarios which would envolve my dearly beloved being sent to the scrap heap, which considering my mother, is a likely scenario.

Please help!

Ps: I feel that I should warn you all that I'm a noob when it comes to all of this, and I may have difficulties regarding acronyms and such.

 

Did you ONLY replace the coolant reservoir? Sounds to me like your radiator is clogged, and possibly as well as some of the hoses. Might need to replace the radiator. You could TRY flushing the system but by the sound of it, that might not work if you are already getting excessive pressure buildup. Sorry to hear of your troubles. Definitely do not run the car too long in it's current state. Overheating can easily warp the head and give you more trouble. I'm sure the more experienced can chime in, as I do not have much experience with such an issue and I can only really speak to what I know. Best of luck!

 

We also replaced the exit tube from the radiator, you know, that S shaped one.

I thought it might be the thermostat, since the water stopped squirting out once the fan kicked in. Maybe the thing got misscalibrated when they switched the tube and now the fan doesen't kicks in at 86 Celcius like it should, causing the water to boil and pressure to buildup.

 

Just posting here what it was, since someone might end up searching for a fix for a similar problem one day and might need it.

Turns out that the mechanics who replaced the tube leading into the radiator forced the thermostat fitting and created a fissure. That was the cause of all this headache.

Thanks for all the help, guys!