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Thread: Heater/Coolant issue: Weird Gremlins

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2013-02-20 16:51:43
#1
Heater/Coolant issue: Weird Gremlins
Okay, here's the deal:

A few days ago I noticed a sudden increase on my temp gauge on my 1988 Pulsar NX, so I put the heater on max power, and highest setting.

However, the air coming from the vents was, well, cold.

I immediately thought that I must've lost coolant, as that would be the cause of both the high temperature of the motor, as well as the cold air from the heater.


When I arrived at my destination, I popped the hood, and sure enough, there was the sound of boiling/evaporating liquid coming from the motor, and the coolant reservoir was almost empty. I hadn't seen any smoke coming from the exhaust, nor could I locate any significant leaks.
So I thought a refill of the coolant would be the solution.


Here's where it's getting interesting.

I was about to refill everything (motor was cold, mind you!), but when I removed the radiatorcap, coolant sprayed EVERYWHERE. It was like there was a lot of pressure behind it. The coolant reservoir was still empty. Here's the funny thing: Besides coolant, there was also smoke coming from both the radiator, as well as from the reservoir. This struck me as odd, because the motor was cold.

I put the cap back immediately, and started the car. After a while, I removed the cap again. No coolant came out, so I poured about 4/5th of a liter of coolant in it. After a while, the coolant began to overflow again (from the radiatorcap). I closed the cap, and poured the rest of the coolant in the reservoir.

I drove home, and after some time and variable engine temps (rising, dropping, rising and dropping again within a few seconds) it stabilized to below half again, and the heater was blowing warm(-ish) air again.

So I thought all was well again, until I drove home from work today, and I noticed a rise in engine temps again, accompanied by cold air coming from the vents. This happened for a few minutes, after which everything stabilized again (sort of). When I popped the hood again, I saw that there was still some bubbling in the reservoir, and you could definitely see that fluids were streaming back into the reservoir.

Finally, when I put the HVAC on max power and max temp now, it's actually very cold compared to what it was before (there's still some heat, but before it felt almost like I would burn my hand when I put it in front of one of the vents).




TL;DR:

What could be the problem when I have the following things happening:

- Engine temps rising from out of nowhere
- Cold air blowing from HVAC on highest setting
- Pressurized coolant spraying from radiator filling point with cold motor while reservoir was almost empty (implying there's plenty of coolant).
- No smoke coming from exhaust (apart from what seems like smoke when first starting up in the morning, but that could be because of the cold)


I have a few theories, but I'd like to hear your thoughts first.
2013-02-20 16:55:04
#2
Sounds like coolant is not flowing.

May be a stuck thermostat or a clog at some point.
2013-04-30 11:37:51
#3
Have you ever changed your tstat.heat fluctuating is caused by an improperly bled system most times.to eliminaat e an air pocket issue start carbleed from radiator cap.coolant gets everywhere but it gets air out.after bleeding still have this problem take out tstat and see if it stops .if not change temp sensor.another thing after you drive the car shut it off n check to see if water pump is leaking
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