Age Old Question. No luck finding an answer.

[busky_j]

Hello there. First post, so apologies if ya'll are tired of seeing this question come up.

CTS, Thermostat, Heater core Flush?

I've read the countless threads on this topic but can't seem to find what the dealy is.
http://www.audizine.com/forum/showth...or-replacement
http://www.audizine.com/forum/showth...ical-Questions


My cars temp gauge slooowwwwlly gets to normal operating position (12 o'clock) when on the highway, running low to mid fan speed but full "HI" heat. When I turn the fan speed up, the temp gauge drops down to the first white bar (10 o'clock). Driving normally around town, (stop lights, not exceeding 50 mph) the temp gauge fluctuates between the first white bar and normal operating position. I'm unsure if the heater core has ever been flushed and am hoping that because she's almost 10 years old, this is the problem.

Just wondering if anyone has had similar problems and a resolution? Or if I just need to start from the beginning, flush the core, and work my way through, change the sensor and finally the thermostat.

Thanks!

[mfdk]

Hello there. First post, so apologies if ya'll are tired of seeing this question come up.

CTS, Thermostat, Heater core Flush?

I've read the countless threads on this topic but can't seem to find what the dealy is.
http://www.audizine.com/forum/showth...or-replacement
http://www.audizine.com/forum/showth...ical-Questions


My cars temp gauge slooowwwwlly gets to normal operating position (12 o'clock) when on the highway, running low to mid fan speed but full "HI" heat. When I turn the fan speed up, the temp gauge drops down to the first white bar (10 o'clock). Driving normally around town, (stop lights, not exceeding 50 mph) the temp gauge fluctuates between the first white bar and normal operating position. I'm unsure if the heater core has ever been flushed and am hoping that because she's almost 10 years old, this is the problem.

Just wondering if anyone has had similar problems and a resolution? Or if I just need to start from the beginning, flush the core, and work my way through, change the sensor and finally the thermostat.

Thanks!

I never paid too much attention when i had the same issue, but i know it was the thermostat because i never see the problem anymore. If you haven't changed thermostat then that will probably be your root cause.

[Charles.waite]

Definitely the thermostat.

[mtroxel]

If you turn up the fan and the coolant temp goes down, I'd say your heater core is working well. You've got a blockage somewhere, and a bad stat qualifies as a blockage. Try that first.

[Audi_509]

Definitely the thermostat.

X2
My termostat caused the same issues.

[busky_j]

**Update

Thermostat replaced. Now there's no heat whatsoever, but temp. gauge hits normal (12 o'clock) position within 5-8 minutes. Top heater hose is almost room air temperature, while it's 28F degrees outside. The bottom hose is warm for sure, but definitely not hot. Next step a good ol' CLR flushing?

Any suggestions would be great as living in Salt Lake City during these times can get quite cold. Thanks!

[allstock]

Purge the system of air correctly.

[fly300kts]

Purge the system of air correctly.

You have air in the system and there is an easy way to purge the system, without any apparel

Phil

[Charles.waite]

I also vote for air in the system.

[aluthman]

Top off coolant tank, let sit. Top off tank again. Drive around until car warms up. Temp gauge will eventually spike. Shut off car and top off exp tank again. Drive around more and then top off one last time if needed. Once done, you can bleed any residual air out of the coolant hard pipe. This is what I do everytime I have to drain and refy system and so far it has worked well.

[Charles.waite]

Also turn the heat to HI and keep it cranked. The heat SHOULD come back quickly but sometimes bubbles get stuck in the heater core and don't let coolant circulate properly.

[busky_j]

Awesome. Thanks so much for the help everyone! I'll give 'er a shot and see how we do.

[80sGuy]

Classic Thermostat symptom. Hope you fixed with it.

[Silveravant]

Heat setting has nothing to do with flow of coolant through heater core. Temperature is adjusted by mixing hot and cold air. There is no valve regulating coolant flow through the heater core.

[busky_j]

Wish these updates would end.

So I've attempted the multiple bleed sites (heater core output hole (top hose w/bleed hole) and hardpipe bleed screw). Heat has always been on HI with medium fan speed (4-5 bars. )I've driven the car around 'til she's warm, bled from sites with reservoir cap off , topped of coolant tank. Let cool. Drive around 'til warm again, bleed from sites w/reservoir cap off, and the tank hasn't really dropped much. I've gotten steady streams from both bleed sites multiple times.

This last time, cap was off for about 5 minutes, hardpipe bleed site produced steady stream, that was tightened, went to bleed from heater core output line and got nothing. NOTHING. No dribble of coolant, no air. I replaced the hose, tightened clamp, switched to DEFROST mode and started to get a little squirt of coolant.

Does this mean I've got a blockage in the core and need to flush it and let some CLR sit in there for a bit? Am I doing part of the bleed wrong? I've read the very information Old Guy's post which has been helpful, but I'm stumped now. Thanks for the help.

http://www.audizine.com/forum/showth...t-quot-problem

[mtroxel]

went to bleed from heater core output line and got nothing. NOTHING. No dribble of coolant, no air. I replaced the hose, tightened clamp, switched to DEFROST mode and started to get a little squirt of coolant.

Does this mean I've got a blockage in the core and need to flush it and let some CLR sit in there for a bit?

Gotta be. Take one of the hoses off again and blow on the tube (it won't kill you, everyone here would be dead if it could). You should be able to blow coolant right through the heater core.

[busky_j]

It's crazy though! Yesterday when I tried it, it was flowing fine through the outlet hose.

[busky_j]

Okay last post about this before I flush it. Coolant reservoir cap off, heater core outlet hose bleed hole off core, when I rev the engine, it sounds like air is purging from the system, but then the reservoir starts to bubble and overflow. No coolant ever came from the bleed hole. Any final suggestions? Thanks a million to everyone who's helped me try to figure this beast out.

[allstock]

When you say you're bleeding the air are you just staring at it expecting it come out on its own?

Motor off.

Open reservoir. Unscrew bleeder tap on metal hardline.

Carefully clamp off the small diam recirculation line from reservoir.

Squeeze the upper rad hose and pause - anything come out? - if air you'll hear it

Place your finger on the hardline tap

Now let go of rad hose

Remove finger from tap

Squeeze upper rad hose - anything come out?

place finger on hardline tap while still squeezing the rad hose etc...

Repeat until you get continuous coolant over flow from the tap and visually see the coolant up to the brim of the tap.

I've done this so many times it's second nature so it may be confusing when I explain the sequence. It works every time.

Highly doubt you have blockage unless you've been running tap h2o in the system for very long. That or it's mechanical as in t-stat or broken water pump.