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Vauxhall Omega, over heating

Hi, I recently had my N reg 2ltr auto Omega's cooling system flushed out with a chemical flush and had it refilled with pink anti-freeze. I noticed there was sand like sludge which came out of the system, even though I'd flushed it myself about 12 months ago with running water. As soon as I drove it the temperature hit 100 and I took it back to the garage. They installed a new water pump and I took it for a spin again. After about 5 miles the gauge hits 97.5 and is on the verge of going up to 100 but comes back down again to rest at 97.5. I still think there's a fault as in the past the gauge never went above 92.5. The fan does come on at 95. I am thinking of changing the radiator fan switch and hope it will resolve the problem.

Anyone got any other suggestions?

The radiator doesn't seem blocked as both the in and out hoses get warm very quickly and the radiator is even hot. The thermostat is also working.

Reply to
hitesh
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hitesh (hitesh snipped-for-privacy@hotmail.com) gurgled happily, sounding much like they were saying :

Airlock?

Reply to
Adrian

In news:Xns9830B42D9A22Aadrianachapmanfreeis@204.153.244.170, Adrian wittered on forthwith;

I suggest that it's not actually overheating.

It's undercooling....

Reply to
Pete M

Pete M ( snipped-for-privacy@bogoffwithzepressedmeatblueyonder.co.uk) gurgled happily, sounding much like they were saying :

Is that like "I'm not fat, I'm undertall for my weight"?

Reply to
Adrian

Reply to
hitesh

Reply to
hitesh

The thermostat is set to open at 92 deg, so that's the temperature it ought to run at.

Question: is there any sign of steam from the exhaust? I ask because there is a known weak point in the cylinder head which allows a leak between the water jacket and no. 4 cylinder. Chemical flushing may well have cleaned out anything stopping this up (and a sand-like sludge hints at a stop-leak compoung having been used in the past).

The cure is to remove the head, have it skimmed, and reassemble with new gaskets etc. Not expensive on parts, but labour will mount up I'm afraid, about 5 hours if nothing else is needed. Of course if your cambelt is due, you can kill two birds with one stone. DIY only if you have a good toolkit! (I've done it a couple of times).

Reply to
Chris Bolus

Hi Chris, thanks for the information.

I'll have a look at the exhaust when I get in tonight. I was hoping to change the radiator fan switch to identify if that was faulty. Lack of quality tools will prevent me from going down the DIY path.

Timing belt was done 3 years (18K miles) ago. One of the Cam belt pullies has got some play so will need doing so will probably get it all sorted together.

Thanks for some excellant advice Chris.

Hitesh

Chris Bolus wrote:

Reply to
hitesh

All the crap that was insulating the temp sender has now been cleaned out, and it's giving a proper reading?

Reply to
Stuffed

I guess you might be right.

I bought a new Radiator Temp switch so will let you know once it's changed and made any difference. Also going to add Greased Lightning all in one coolant, as I had this in there before and it kept the temp's down. Also going to add Stop IT Engine Leak just incase there is a leak in the engine.

Hitesh

Stuffed wrote:

Reply to
hitesh

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