What did you do to your P2 Volvo today?

[vtl]

Idled for 10 minutes today and my heater core exploded. Coolant leaked inside the car. All I heard was hissing and then steam. Not sure if the heater core was just due, or there are exhaust gasses in coolant system that caused to fail early.

I will be watching the peppermint video on this, but if there are other inputs on this so I can more safely tackle it, I am all ears.

Exhaust gases get into cooling system.

[dikidera]

Idled for 10 minutes today and my heater core exploded. Coolant leaked inside the car. All I heard was hissing and then steam. Not sure if the heater core was just due, or there are exhaust gasses in coolant system that caused to fail early.

I will be watching the peppermint video on this, but if there are other inputs on this so I can more safely tackle it, I am all ears.

Exhaust gases get into cooling system.

I am thinking about it, yes. About 2 months ago I think I did a block test and it came back normal. If I can manage to install the new heater core tomorrow I will immediately check for exhaust gasses again.

If there are, I am suspecting a cracked block or something. I have new evidence to suggest that under high loads(frequent WOT and redline even the 140hp detuned version can crack it, a guy I know is ordering his second block for the NA engine and claims that is what he did)

[dikidera]

I managed to remove the old heater core without disconnecting anything around the rack. Installing the new heater core was more challenging and did result in some bent fins, but still better than being cracked.

I put in new o-rings on the metal pipes and used dishwashing liquid on them since it's something almost every mechanic has done on o-rings. I wonder if the pipes should stay fitted inside, I can press them in the heater core, but they are not staying fitted in and come back out. Which prevents me from installing the metal clips easily, which sadly did get bent and I had to straighten them as best I could, but still, a challenge to reinstall and my only pet peeve at the moment. Of course because the pipes come back out I need to simultaneously press them in whilst installing the metal clip which is very very difficult. I am hoping if I can install them, that there are no leaks. If i cant reinstall these clips I plan to order new ones.

[BlackBart]

I often use rubbing alcohol on o-rings and tight hose fittings - they can slide together, and then it evaporates.

[dikidera]

Well so far so good, installed new heater core matrix, took a while for the air to burp out and verified no leaks. Now...the problem is after the antifreeze recirculated I saw quite a lot of small bits of oil floating inside coolant tank, not sure if it's from way way back from a year ago or fresh engine oil(indicating oil cooler is damaged or headgasket leak). The coolant hoses do feel on the firmer side of what I would expect, so..we shall see.

I've been made aware that oil in coolant is usually not a symptom of HG but more likely oil cooler leak. Exhaust gasses on the other hand are entirely different matter but I will test soon.

[abscate]

MVS users don’t get cracked heads. Your heater core just reached its end of life. Make sure your fans are working otherwise you will get high pressure at idle warmup.

[dikidera]

Well I didn't specifically say heads, more like block or the better outcome, an oil cooler leak. Anyway, after leaving overnight with the cap off, the coolant had further dropped and topped it off. By now the system should be nice and dandy. As for over pressure from a cracked/warped block or failed oil cooler, I will see.

Of course I will still do a block test. I've speculated for a while that CO2 can dissolve in engine oil and may sometimes produce a false positive if there is engine oil in coolant.

[jonesg]

Replaced cracked coolant tank and short turbo coolant hose behind the engine ,not bad so far
I thought while I'm at it I ought to swap the thermostat out, I think vida ought to say.."first remove the engine."..

or maybe leave the engine and remove everything else.

remove serpentine belt, remove plastic computer box, unbolt P/S pump and disconnect the high pressure line so the pump can be shifted out of the way. Didn't spill much brake fluid because the steering rack self drains constantly.
Remove the large rad hose from thermostat housing, now you can actually see the torx bolts and have a straight shot.
I broke them free with 3/8 ratchet using extended 4 inch torx drivers then zipped them out with the elec ratchet.

Now I have to put it all back together.

[vtl]

Jonesg need a better selection of extensions and torx heads I managed to replace T-stat assembly without removing anything else.

Also PS pump can be removed without touching computer box, just use 1/4 ratchet with deep 10 mm socket.

And also get a "OPK12 Rubber Vacuum Cap Assortment" to plug both the PS pump and pressure line

[abscate]

That’s a nasty job on the P2