Maybe some BB members may remember my summer time posts
about my coolant blast/fog emmiting heater core problem.

Some strange things are going on here. Maybe some veterans Volvo folks
can confirm or deny my findings.

Facts :

My c70 is almost four years old

No coolant on cabin floor

When temperature is 60 deg. or above I get a nice blast of coolant bomb

When temperature is 60 deg. down to 50 I get a little blast of coolant

When temperature is 45 deg. and lower I get NO blast of coolant. All's fine.


So, is my question is, as Volvo heater cores age do they emmit a little
coolant bomb at warmer temps and function perfectly fine at winter temps?

A neighbor[mechanic] says this is common on all older cars.
Maybe cold climate owners can supply some input.

My concern is that money is tight and some have mentioned that the
dealer may make me flip for part of the heater core replacement
and/or climate control work.

If my above findings are confirmed I may just live with using the heat
below 50 degrees which is fine with me.

Any feedback appreciated, especially from older Volvo owners who live cold
regions.

Thanks,

rd 99' c70 hpt

What is a "coolant bomb" and a "coolant blast"? Are you literally getting sprayed by liquid coolant? How often do you have to add coolant? what is the rate of loss?

Coolant bomb and blast = coolant smell and sometimes fog. No liquid.

Coolant loss = 2 inches[reservoir] in summer but may stop in cold months.
Watching it.

rd

Spoke to a knowledgeable Volvo person[emp] today. He says
heater core problems on 99's and later are extremely rare.

He feels I may have an internal hose/clamp leak somewhere from
the firewall in to the cabin versus a leaky heater core.

He may be right as I have been losing small amounts of coolant.

Does anyone know where weak spots [ in 70 series] may be in the
hoses or clamping from the firewall in to the cabin piping?

This may help me and tech narrow down the problem.

TY

RD

I have the same problem with a 98 S70...did the dealer say anything about bad heater cores in 98's? thanks.

No Jeeter, he didn't say about 98's.

Are you getting the same simptoms as me. Another words the problem
rectifie itself at colder temps.

rd

rd,

no, I always have the smell for a second or two when I run the heat/defrost. It goes away after a minute, but it is just as bad during the winter. My fluid loss is very small, in 1.2 years it has gone from the top of the full mark to just halfway inbetween full and add. I hate the smell, I think i will try to pull the carpet back...

jeeter

Move the carpet, remove the plastic cover just to the right of the gas pedal, left side of heater core and look at the heater core compartment and 2 tubes that go from the firewall to the heater core. There are NO clamps there, they're sealed by o-rings but I've seen those o-rings leak too.
Considerering your symptoms, I'd suspect the core is leaking and it'll be obvious when you look at it. If there's any doubts, you can also have it tested with coolant pressure tester. The good news is that it can be replaced w/o removing the dash as there's 4 screws that hold it's housing to the climate systems housing. Don't let anyone tell you that the dash must be removed for THAT.

Yeah Vinny,

I pulled the carpet about 3 different times since this summer
and did not see or feel any coolant from the heater core housing,
the 2 tubes which go into it, or any coolant just below on the padding
below. Does that help me in my troubleshooting or not really.

Could I have a small leak where the piping traverses the firewall?

Are there any key places to look for a leak?

Also, why is all fine now that it's cold out? Strange.

Thanks,

rd

So if I see a leak, do I replace the O rings? (is that possible?). How would I know that the core is actually bad, and that it's not the connections? I can do most stuff on my car, is this a big job? thanks.