Car too cold

First off, I will say that I have a few electrical abnormalities that I have on my list of to do's that may be my problem, but I doubt they could be affecting how much heat I get in the car. I changed out the thermostat for a 195 degree with little or no change that I can notice. The blower fan seems to be working properly, though, who knows until I take things apart of course.

What, other than the thermostat can affect the amount of heat in the car? I have had this one for 7 years, and I'm doing everything the same as I have before. (I have never needed to block the air cooling the rad, even in extreme cold).

Thanks!

Jai

You may have a partially blocked heater core. You may be able to tell by disconnecting the hoses at the firewall and flushing with a hose. I wouldn't put much pressure on it, but you shouldn't need much to show that it's blocked.

Disconnect the input and output to the heater core.
Flush it in reverse. I used a portable pump (attached to a drill) two pieces of clear tubing and a bucket to continuously flush for about 15 minutes. I used water with some CLR in it. At then end, really flush well with clean water and then water with some soda water to neutralize any acid left.

That did it for me. Got the heater again.

When you go to flush the heater core it would also be a good time to change out the coolant. That way you can make sure that nothing else will go and clog what you had just flushed out. In turn restricting the amount of heat output you could be getting.

Thanks for the ideas so far!

My car is a 95' 3cyl 5spd with about 235 000 km (146 000 miles)

The temperature here dropped to -35C (-31F) the other night. It's now way too cold to fix it now, but as soon as it warms to -20C (-4F), I want to be prepared. I have a bottle of CLR and 24 inches of 3/4 inch coolant line to replace the lines in and out of the heater.

I agree that this is an opportune time to change the coolant. I was thinking of flushing the whole system, but I've heard that this can be a bad thing if the rad is old. Any opinions?

How do I attach the garden hose to the coolant line so I don't get water everywhere? Anyone know of an adapter for this?

Jai

Wow, these heater cores seem to plug up a lot. I think when I decide to replace mine, I should put some kind of inline sediment catcher in the line, to catch debris that tends to clog it up. I've had to blast mine out a few times in the past and now, it is partially plugged again. I was wondering if someone can tell me exactly which is the inlet to the core, so I'll know which hose to install the sediment catcher.

I think it's the left side. Just trace the direction that the glycol moves through the coolant lines starting at the block. It moves from the block to the rad, and then into the heater core where it goes into the head.

It's cold here in Edmonton 6 months a year, which means my heater core has put in a lot of hours. After 7 years owning this car, and I'm pretty sure that it;s the original core, I have not changed the glycol, nor have I done any other work on the coolant system. I am not about to start complaining about this system! Now, my electrical system is another story.

If other peoples metros are plugging up a lot, I think it may have to do with age. I've not heard a lot of complaints about this problem before now. Maybe all of MK3's are getting to that age that the slow internal rusting of the rad and heater core are causing large enough particles to dislodge from these parts and cause blockages. I am just speculating of course.

Jai

Yea, I think you're right. I looked into my radiator in the past and noticed a couple blocked veins, but my car never runs hot, so I never worried about it. At the hottest, it may creep up, just past the half way mark. I can tell when my heater core clogs, because my temp gage needle practically oscillates back and forth in a 1/4" range. I will probably replace both, the core and radiator this summer, just to be on the safe side.:smokin:

Jai,

-35C, you must be from Canada.
I purchased a Y adapter at Canadian Tire, specifically designed to flush the coolant system. It allows you to connect a garden hose, without too much effort.

For the flushing with CLR, I just connected clear PVC tubing directly to the core nipples that show in the engine compartment. Don't forget to really flush with clear water, and optionally with soda water to neutralize the acid. CLR will eat the metal...

And yes CLR or other flushing agent might disolve deposit that have been hiding a leak for year...

Yep, Canada. We get a bit colder temps up here. I was looking at the coolant hoses and thinking to myself, why don't I just bypass the rad during the winter months? I am thinking about taking the coolant line coming out of the head and connecting directly with the horizontal tube? There would be less heat lost, but I wonder if it would be too hot. Anyone ever do this?

Jai

Yep, Canada. We get a bit colder temps up here. I was looking at the coolant hoses and thinking to myself, why don't I just bypass the rad during the winter months? I am thinking about taking the coolant line coming out of the head and connecting directly with the horizontal tube? There would be less heat lost, but I wonder if it would be too hot. Anyone ever do this?

Jai
I'm not sure what part of the cooling system /Flow your attempting to bypass here Jai, But I doubt that any bypass process will work. The coolant flow is specific in these cars and there are sensors (Coolant Temp Sens) that most likely will be bypassed also (If bypassing the intake Manifold). My :2cents: says that if this car has not had a Thorough flushing of the Entire cooling system in awhile (If ever).......It time to do it! Live with the heat for a month or 2.......Then flush out the entire cooling system good 3-4 times. Start by flushing the heater core itself in Both directions several times by pulling of both the hoses from the heater core, Then re-attach the heater core hoses. Then get some "Prestone Super Flush" and follow the directions for usage......And dont be afraid to repeat the process again! Remember! Turn the heater on the HOT Temp setting, Blower motor on Full when flusing the system. Then put in a mixture of at least 50% NEW, Green anti freeze and 50%Distilled water mixture in the entire cooling system. (Check your cooling system capacity specs before refilling the Radiator). Up the ratio of anti freeze to 60% or so if the temps where you live get around Zero degrees. It took me 3 good flushes of the entire cooling system to get my 94 Metro back up to full good and HOT Heat after it had sat for 2 years when the original owner blew the engine up on it, and I bought it from Him.