no heat - winter is coming.

[gabejones]

Do the heater core while you can!
Mine blew up two days ago without warning and left me stranded far from my space & tools.
No choice to send the car to a Volvo shop. Looks like it is a hard work ahead said the Volvo tech...

So just do my heater core and see what the heat is afterward? Even though it could be the blend doors? I mean there are two blend doors, so since both sides have the same problem it's probably not that right?

Are HC doomed to clog up at some point no matter what?

[cn90]

Check the blend door arms. Info in my heater core DIY...

[Antoine240bk]

If it's only the blend doors arms, hope you will resolve this. Anyway it's time to chase HC or any coolant leaks at that mileage.
This is the second car that have a failed heater core. Very frustrating after the radiator, coolant tank, hoses replacement on the XC70 six months ago, so it took me by surprise. I guess assembly of the HC are made of plastic and it does not last.

[abscate]

See cn90 thread on p2 heater core repair. If the one arm of the linkage falls off I think you lose heat on both sides. It’s hard to imagine the core will plug if the coolant looks ok.

[cn90]

The HC in BMW lasts some 20-30 years bc it only works when demanded.

The P2 Volvo HC is hot all the time, so the lifespan is significantly reduced. They should have designed it like Honda or BMW: when you ask for heat, a valve opens, allowing hot coolant to flow into HC, it takes a few sec then you have heat. In contrast, the Volvo system gives you heat instantly (vs a few sec)...You gotta loooooove the Swedes lol...

[gabejones]

Hello again, the project is nearly complete. Reporting in to review the issues.

The movie of this would be a comedy of me folding up into the floor and swearing and even laughing and yelling. As 6ft 2" and not especially bendable at 46 yr old, (ruptured disc in neck, etc...) my esteem of mechanics is growing. My tools and skills could clearly improve, and this was a first time job... so would go better if done again... I digress.

The newest issue is burping the coolant system. I flushed with distilled water, but I'm seeing that it's hard to get a full 2 gallons out of the car from the radiator drain. I got only one gallon out of it after flushing and testing the HC matrix - which is producing good heat now.

I did not measure all the water in the pan until I put in a gallon of coolant mix and encountered a full reservoir. So now I'm concerned I have a coolant mix that is closer to 25% coolant than 50% due to the flush water remaining. It takes much more time to gurgle the tank and get it full than I thought.

The aftermath of the project also left the retaining clips in the HC tube connectors very mangled and not installed in the same way. Removing the clips was tougher than expected, but inserting them was full hell. Because they splaying outward as I inserted them the tips of the clips would encounter the HC housing and become stuck. One tooth on one clip actually went away, protruded out from the channel. One of the clips was simply not budging and would not go all the way in, although there is pressure on the flange of the tube on two sides, it just looks terrible. The O rings are engaged and mangled clips are firm in place though so no leaks. I am just going to have to live with it.

Everything took much longer and was more painful than expected. Even the brake light switch removal was hard to do and not intuitive, and I had to look it up how to work the moving parts. It almost seems worth paying the $1000 for a shop at this point. (not really)

[jonesg]

theres a coolant drain on the back of the block, near the oil cooler.
Auto part store sell coolant testers.

[cn90]

- The coolant drain plug on the block...best is to avoid it!

- Also radiator drain petcock...avoid it.

- The coolant burp process: just drive around neighborhood until hot, then you will need to add more coolant later.
The coolant strength...if you already "messed it up", no big deal, after a few hundred miles, measure the coolant strength and adjust it later...

[erikv11]

Access is the only issue with the coolant drain plug in the block. Some find access difficult, some do not. I like using it; I access it from the top to slide some tubing on the nipple, then finish up from below and drain into a bucket. Otherwise it works exactly as intended, is not fragile, etc.

Petcock is fragile and there is wide agreement to avoid it.

If you had pure (mostly) water in there when you added very close to one gallon of coolant, then you are completely fine. Full capacity of the cooling system is close to 9 quarts so it only needs another 1/2 quart of straight coolant to reach 50/50.

Drive it around, if the level drops then top off with coolant until you've added another half quart, after that use water if/as needed, and you're all set at close to 50/50. I've done coolant that way on my Volvos for 20 years.

[cn90]

Re Engine block drain...there is more to it: besides the difficult acces, very often, it is seized and very difficult to remove, whether it is Honda, BMW or Volvo.

This is why I undo the lower radiator hose and drain it there.
Then fill with a few gallons of distilled water (which is ~ $1.50/each)...It works much easier this way.

Then do a rough calculation and add appropriate amount of pure coolant +/- distilled water.

Then check coolant strength after a few wks of driving.