Engine temperature fluctuating after cam belt change

[fester_99]

Hi All,

I’ve got a ’99 Toledo 1.8 SE auto. I had a cam belt change yesterday and driving to work today I noticed that the temperature gauge dropped form its normal position (90, half way up the gauge) down to just above the quarter mark.

This happened as I was on the motor way, once I was back in slow moving traffic it went back to 90.

I’ve had the car a year and a half and all this time it has never moved off 90 once it’s warmed up.

Is there any thing the garage could have screwed up while changing the belt that would cause this? Or does this normally happen when a cam belt has been changed?

Thanks for any help.

 

[Saul]

i wouldnt have said it was normal, could be the sensor or the waterpump (driven off the cambelt)

 

[fester_99]

Thanks for the reply.

I don't think its the sensor, I had that go last year it stopped measuring all together just stayed at the bottom of the gauge the whole time.

Could the water pump cause the odd change in temperature like that? what is likely to be wrong with it?

 

[Ruddmeister]

When I had the impeller on the water pump go the symptoms were the opposite (OK so it was the 1.8T engine but anyway) the impeller in it's part broken state could cope in traffic and low speeds say under 50mph.....only when you used the power did engine temps soar towards 90 degC and off into the Red.

 

[fester_99]

Is it possible that the cam belt change has actually improved something? e.g. all the time I have had the car the engine has been working under stress (which is why it was always @ 90) and now its actually working the way it should do?

 

[Stubill]

No. Once warmed up it should always sit at 90.

 

[fester_99]

d'oh!

So it sounds like something is busted then.

They just changed the cam belt (none of the other bits or belts), what is it they are likely to have broken in the process of doing that?

 

[Stubill]

Your engine temperature (actual temperature) won't fluctuate downwards as you describe from your dash gauge.

First thing I would check is that they haven't disturbed the connector on the back of the engine temperature sensor or it's got damp / crap in it.

 

[fester_99]

Thanks for the info stubill.

I paid closer attention to the gauge on the way home tonight, did pretty much the same thing, in slow moving traffic stays @90, on the motor movies (almost randomly) between just over the quarter mark and just under 90.

Interestingly with a few minutes of hitting traffic the gauge was back on 90.

I noticed the engine seemed quite tight as well, like it didn't want to rev much above 4000 rpm, is this normal after a cam belt change?

 

[Stubill]

Best thing to do is get your car hooked up to VAG-COM - it will tell you what the problem is.

However, if you have an SE, I take it you have climate control ?

1) press the recirculation button and the up arrow button simultaneously
2) us the + or the - button to scroll to 51c
3) press the recirculation button again

This will display your engine temperature - if you do this after a cold start you will see it rise gradually as the engine warms up.

Compare the climate temp display with your dash. If the readout on the climate does the same fluctuation as the dash guage then I suggest you either have a fault in the cooling system (thermostat or similar) or a faulty engine temperature sensor.

If the climate control readout stays steady while the dash gauge flauctuates, I would suggest the dash guage or it's connections are faulty.

And no, an engine shouldn't feel tighter after a cam-belt replacement - not unless something quite wrong was done during the proceedure.

Hope that helps.

 

[fester_99]

Thank you stubill, yes I do have climate, didn't realise it could do that! pretty cool.

I take it the read out the climate control will give me uses a different sensor to the one the dash gauge uses?

Will the climate control continue to function while its displaying this diagnostic information? Also how do you get it to go back to its normal display?

Thanks again, for the info! looks like I will have to get a decent garage to sort out the cocked up belt change.

 

[Stubill]

I *think* it uses the same sensor. The climate needs to know when the engine is warm to avoid blowing cold air when you have asked for warm.

Use recirc and up arrow simultaneously to get back to normal readout.
Climate functions normally when in diag. mode.

 

[fester_99]

Good thinking on that idea Stubill.

The temp read out on the climate diag didn't shift off 90 once it was warmed up so they must have got a wire lose or something.