Irregular Temp Guage

[symple]

This all started last week when the temperature here started staying consistently below 40 degrees.

While driving around, after letting the car warm up, my temp guage rises (noticably fast) almost to the red mark. The heater, even though turned toward the 'hot' setting blows cool air. Occasionally, the heater will blow hot air. When it does, the tem guage returns to normal (about half). The process usally repeats itself, but with no particular order.

I haven't actually seen any antifreeze leaking out anywhere, nor did I see the overflow bottle with anything in it. The car DOES have antifreeze in it.

Any suggestions?

Thanks,
Symple

 

[Lordpaxin]

Sounds like your thermostat is sticking man,

 

[GTM]

Originally posted by Lordpaxin
Sounds like your thermostat is sticking man,

That certainly could be part of the problem. However, I'm more inclined to think the radiator coolant has gotten too low and should be filled when the engine is cold along with the overflow bottle.

When it gets low the pump isn't circulating but as it warms up air pockets will expand enough for it to send a charge of very hot water up to the temp sending unit which goes max scale. The air or steam, now because of this activity, comes to the top but doesn't have enough latent heat to maintain the sensor (steam may be hot but not dense) isn't enough to keep the needle up so it drops back down until the next cycle. With the water not circulating nothing is getting pumped into the heater core hence it blows cold air.

As we should all know the heater is a real pistol to purge the air for it's higher than the top of the engine so that takes some doing. It is of utmost importance the system gets filled ASAP before any damage occurs. It probably will take a 2 liter bottle of water or coolant with a 50/50 mix before they drive to work.

They need to remove the radiator cap first thing in the morning, fill and run the car for maybe 1 min with the heater temp control turned to max, the fan can be on low. Again check the coolant level and add until full, restart the car and let run for 1 min, check again and this time fill bottle to max line. Run the engine until you feel heat coming from the heater, this should allow you to drive without endangering the engine. Have a professional check it if there is any doubt, and the owner should check the overflow bottle level every day for several days. This could be the tell tail signs of a blown headgasket.

Cheers,
GTM

 

[symple]

Thanks for the info guys, I'll try and see if i can get it resolved this afternoon after class.


--Symple

 

[Defiant]

I second GTM's guess. Do you know if your coolant level sensor is working?

 

[GTM]

Originally posted by Defiant
I second GTM's guess. Do you know if your coolant level sensor is working?

Whazzat? (humor)

Good thing you asked, a burned bulb could have not given the early warning. I gotta admit to not watching those stupid idiot lights when they go through their test sequence. And of all the things to have burn out and not tell you is the check of the check. huh... well that's what it does. Anyway you don't notice that it's gone because you can't see it. That's all right I look under the hood once a year whether it needs it or not. hehehe

Cheers,
GTM