[Mk2] [NA] Overheating and no hot air from heater

[Kenn]

Hi,

First post and all that and the car is in the garage but looking for some advice.

My 1994 G LTD rev 3 has been suffering lately. I noticed whilst sitting in traffic that the heater would start to blow cold air out but then blow hot when moving. Wasn't much of a problem as the summer was here so, not being overly knowledgeable on the mechanics of cars thought nothing of it.

Now the concerning bit. I was sitting in traffic on my way home from work in some rain a week ago and noticed the engine temp had gone to about 3/4. It normally sits just under half way. Once I started moving it dropped down to normal levels. The next day the car was fine.

2 days later the wife was driving it for work and made about 2 miles in traffic and she saw the temp get really high. Luckily one road away from home so she dropped it off etc.

I looked at it as best I could and thought the coolant might need topping up, but decided to get it to a garage straight away to see whats going on.

The garage said intermediately that they didn't think the head had gone as the hose pipes were not solid and that the engine coolant looked ok. They currently have the car and are changing the Thermostat over as they also said that they couldn't see the radiator leaking anywhere.

Does all of this sound feasible? Is the engine coolant linked in some way to the cabin heater?

Thanks

Kenn.

[foxy-stoat]

Errrrr yeah !

Sounds like you have an air lock tho. If you get the garage to put a genuine theremostate in and Toyota Forlife coolant and much sure they know how to bleed the system properly, you should be a-ok.

Theres a guide in the Knowledge Base for removing air in the system.

When your stationary, the coolant will be pumped round the system a lot slower than if your on the move, so if you have an air lock or low coolant, your temp gauge may well do funny things.

I'd keep an eye on your coolant an a daily basis until your happy that your not losing any. There are numerous areas where you will lose coolant but you wont see any evidence.

As long as you dont drive when the temp gauge is in the red, or put cold water in a hot engine, you should be fine.

[Kenn]

Ok. Sounds like they might be onto something then.

Don't want to let the girl go. Had her for almost 5 years now and she has been really reliable.

Really must get myself on some sort of part time mechanics course to learn how to do stuff myself.

Thanks for the reply. Much appreciated.

[foxy-stoat]

http://www.imoc.co.uk/forums/kb.php?mode=article&k=38

Is all you need to know really.

[daveslater3110]

Check your radiator fans aswel bud, if its heating up in traffic and dropping on the move, that might be why.

Like foxy said aswel, could be an air lock and also make sure its definatley DEFINATELY a toyota thermostat from the main stealers, mine was £25 with the gasket, bloody cheap to say it'll avoid killing your engine.

I had a blueprint thermostat from a parts shop near me, made my car overheat, wasn't opening enough to let the right amount of coolant through or fast enough. Got the toyota one and its been workin a treat ever since!

Hope you get it sorted mate.

Dave.

[Kenn]

Got the car back today. Thermostat changed and it seems ok.

Left it idle for about 10 mins after a 20 min run. Didn't overheat.

Next test will be when I drive home tonight whether the heater will heat up without moving first!