Major overheating

Inexperienced Joined: Oct 12, 2009 Posts: 36

Afternoon guys.

Firstly, I know this question could pose many answers, but as I'm not good mechanically (apart from the old minis), I feel I will have no choice but to take it to a mechanic unless you can come to the rescue and it turns out to be a job for a simpleton like me.

Anyway, 1995 Coupe 2.6 v6. Overheats on normal around town driving. Water does get hot, even to the point of blowing it out from somewhere around the top up tank (didn't look cool on the streets of London). So, water gets hot, temp gauge just keeps going up, fans do work but normally too late by then.

Points: I have put too much oil in it and also too much water.

Any thought welcome before I give my hard earned to a mechanic?

Many thanks in advance,
Caddyman

Posted: Mon Apr 19, 2010 2:40 pm

Oil and water overfill shouldn't be an issue if it's not been much overfull not good practise with the oil, and water should always be coolant mix, never plain water other than emergency.

You could try a few things that are not expensive, thermostat, either test or simply replace, check if rad is getting hot all over when upto temp but before it overheats, if it is over heating due to coolant being pressurised with exhaust gases the rad hoses will be stiffer to squeeze than normal and it will vent the pressure via the expansion cap valve..

You may also find the heater will go hot and cold as the waterpump struggles with the pressurised coolant too. If it points to this You can try adding some K-Seal..(google it) it does actually work sometimes, or you could have an exhaust gas test at a garage to see if the coolant has combustion gases in it..

Inexperienced Joined: Oct 12, 2009 Posts: 36

Many thanks, appreciated as always.

I'll try the therm first. Do you think a complete novice could fit one without instruction though?

As an note on the gases. i've noticed that even though I use blue fluid, it alway turns red!!! hhhmmm

Cheers.

Posted: Mon Apr 19, 2010 7:17 pm

If it's the same V6 they fit to the A6 C4 I have Bentley info on it, what is the engine code should be in the service book or first part of engine number on log book like AEL AAT for example (tdi models)..

Seem to remember posting this info for someone else, will try to find it, may have been a PM so will be gone now if so..

Sounds like it could be exhaust gases in cooling system if your coolant is changing colour, It may have been like it for a long time just now it's got bad enough to affect coolant circulation, or more than the expansion cap can vent off..

Posted: Mon Apr 19, 2010 7:19 pm

If it's the same V6 they fit to the A6 C4 I have Bentley info on it, what is the engine code should be in the service book or first part of engine number on log book like AEL AAT for example (tdi models)..

Seem to remember posting this info for someone else, will try to find it, may have been a PM so will be gone now if so..

Sounds like it could be exhaust gases in cooling system if your coolant is changing colour, It may have been like it for a long time just now it's got bad enough to affect coolant circulation, or more than the expansion cap can vent off..

Posted: Mon Apr 19, 2010 7:21 pm

for some reason it wont let me edit or delete my posts it's suspossed to read A6 C4 in the first posting

Inexperienced Joined: Oct 12, 2009 Posts: 36

Thanks much.

I think I'm going to give it to my regular mechanic, as i know how the simple jobs go pear shape and this doesn't sound simple.

After chatting to mechanic he said it maybe effected by gearbox. Some sort of leak, mixing fluids etc...

I think I'll leave it with him and hope my repeat custom (18yrs) keeps the cost down.

I shall let you know the outcome for future reference.

Russ

Posted: Tue Apr 20, 2010 12:58 pm

Only on and automatics that would be either be ATF in the cooling system which would make mayonnaise similar to engine oil mixing with coolant, or the other way, coolant in the gearbox oil both could be caused by a leak in the radiator core on cars that have joint ATF / coolant rads.. I can't see this being related to your issue or how it would cause overheating, but it is often hard to armchair diagnose cars Wink

Inexperienced Joined: Oct 12, 2009 Posts: 36

Outcome: Gave the car to my usual machanic, who whilst is trustworthy, is not an audi specialist. He drained the system, filled back up and seems ok. He couldn't look at thermostate as it's behind cambelt. £400 labour as might as well do cam change whist there. My car is an auto.

Basically, if it overheats again, i will have to shell out or sell for scrap - which is a shame as its in good nick otherwise.

Thanks for all the help,
Caddy

Posted: Tue Apr 27, 2010 1:38 pm

If the thermostat is working and fans are coming on check the water pump vains haven't come off the pumps shaft. This is what happend to my 20v thus causing the same issues you have changed the pump and cambelt etc and it's been fine try and get a water pump with metal vains and not plastic think they are more durable

Posted: Tue Apr 27, 2010 1:49 pm

Thremostat is in the cambelt area but it can be done without removing cambelt, will have a look at my bentley manual tonight, what is the engine code btw?

Posted: Tue Apr 27, 2010 9:10 pm

Imo you really need to find a garage that can test for test for thermostats working on not quite easy to test without replacing (although it could be randomly sticking closed which is unlikely), and a simple exhaust gas test of the cooling system before doing anything else..

It could be broken waterpump drive but I would think that would lead to very quick overheating and always be the same, in others words you wouldn't be able to do 30 miles one day then only 5 the next before overheating.

Posted: Tue Apr 27, 2010 9:27 pm

This forum is very annoying Evil or Very Mad

is there a reason why you can't edit or delete your posts?. I have to keep reposting if there is an error as I can't correct it..

Imo you really need to find a garage that can test for thermostats working or not, quite easy to test without replacing (although it could be randomly sticking closed which is unlikely) and a simple exhaust gas test of the cooling system before doing anything else..

It could be broken waterpump drive but I would think that would lead to very quick overheating and always be the same, in others words you wouldn't be able to do 30 miles one day the 5 the next before overheating

*edit option fixed now thanks* Wink

Posted: Tue Apr 27, 2010 9:46 pm

If the fans are running then the thermoswitch in the radiator is detecting hot coolant which usually means it's circulating around the engine block. The only time the fans run is if you have air con and it's switched on. It would seem the the thermostat is open for the radiator to receive hot coolant. I've had a V6 where the water pump impeller had come loose and not pumped coolant causing the engine to overheat. I've also recently had a V6 where the coolant system was partially blocked with rad-weld and heavy sediment. This had the effect of turning the coolant a rusty colour. Your mechanic would be right to change the fluid and it would be good to get the system flushed. There is an engine block drain hole at the back of the block where the gearbox bolts to the rear of the base of the block.

Inexperienced Joined: Oct 12, 2009 Posts: 36

Many thanks Guys. It's running ok at the moment.

Unfortuantely, if it does go wrong, I'm not going to be able to do it myself, so v. costly.

I may scrap it an get a Pug 306 GTi6 that i've always wanted.

It means I will have to join the Pug forums thought and I think they'll be a younger crowd. Wicked!!!

Best regards,

Audi Nut Joined: Feb 23, 2010 Posts: 71

woah.. talk about extreme.. lol

seriously though, stick with it, as has been said the thermostat can be changed without the cambelt being removed by using a special jig to keep it in place, even if it is the waterpump its fairly standard practice to replace common failure plastic impeller pumps with metal ones at a cambelt service anyway.. and surely £400 is cheaper than a even the scriffiest pug shopping trolley?

keep the faith chap.

Posted: Wed May 05, 2010 8:27 am

Don't do it keep the 4rings trust us you will never get another car

Camped on the site Joined: Apr 28, 2006 Posts: 283

nah go for the gti6, 160bhp 6 gears blah blah and sell me the v6 for scrap value Very Happy

Posted: Thu May 06, 2010 9:48 pm

Not as much of a worry as a Renault, but you'd still want your RAC card with you at all times Laughing

Inexperienced Joined: Dec 03, 2012 Posts: 22

cheaky git younger crowd Sad

the audis a great car

Posted: Sat Dec 08, 2012 10:11 pm

You can tell if the pump is working as you can see coolant being pumped in to the expansion tank by the small pipe on top of it