Overheating still

[sam2.0 10]

Took my 2.0 16v on a longer journey today, it got up to temp ok and ran fine, but as soon as I hit a bit of traffic and slowed down the temp started to rise, luckily I was at my destination, so just turned the car off.

 

Set off home again a few hours later and got most of the way home and the temps were high again, this was with me driving along. I pulled over and let it cool before driving the 2 miles left.

 

I managed to lower the temp both times by putting the hot air on and keeping the revs higher to get the pump working, it'd lower it by a few degrees.

 

I've changed the following:

 

Coolant

Coolant hoses

Water pump belt

Thermostat

 

My rad has a tiny tiny leak, which I will replace, but would it cause the car to overheat?

[floppyman 0]

Dont think the small leak will cause it.

Do the fans kick in?

Start the car at idle and remove the small hose from the coolant bottle and check if you have a flow. If not raise the rpms a bit .

Might be your water pump thats gone. Dont know if these engines have the plastic or metal impeler.

[sam2.0 10]

The fan kicks in, pretty sure on the 2 step speed too.

 

Pump was my first answer, but the belt snapped recently and the water got hot so quickly, I doubt the pump has failed as the water still takes time to get hot.

[sam2.0 10]

Bump.

[sam2.0 10]

No help?

[carrots 1]

it could be the water pump,or even the headgasket

[sam2.0 10]

Ruled out the headgasket: http://the-corrado.net/showthread.php?76279-Water-in-oil

 

Water pump works, is it not just a works/doesn't work, or can it be broken?

[carrots 1]

does it build up presure very quick.any steam out the exhaust.does it misfire when you start it in morn

[sam2.0 10]

Smoke/steam only when the engine is cold and its cold outside.

 

It does misfire on first start, for 10-20 seconds. I recently replaced the sparks which cured this, but its come back.

 

Pressure build up quickly? The cylinders all have good pressure.

[carrots 1]

yer if you start it from cold let it run for 30 secs.take the water cap off ,has it built up a lot a pressure in 30 secs.i had same sort of prob with mine i changed everything then took head off to find it was cracked

[sam2.0 10]

I'll try at lunch. I also have a coolant pressure gauge, which showed the pressure going down very very slowly, which implies a leak, but it could have been the small hole in the rad.

[northG60 0]

thermostat can also cause weird running temps i beleive

[sam2.0 10]

thermostat can also cause weird running temps i beleive

 

Done it 3 weeks ago!

[sam2.0 10]

Thought I'd update this thread.

 

The car was hardly used since I saw this problem, manly short journeys if I couldn't get access to an other car.

 

I was prepared to do the head gasket and all cooling elements. But I decided I'd do them one by 1, just to see what the issue was. I started by draining the coolant and checking the oil/water matrix cooler, no water flow issues.

 

Previously I'd ruled out the water pump in my head, as it's so simple its just a belt on a pulley, the pulley moves, so it must work! Anyway, a mate said the race cars he looks after have pumps go but still look fine. So I went for it, changed the pump and thermostat (its very easy to do when the pumps off the car, so figured what the hell, even though it'd be done a few months back). Ran the car to warm and took it for a drive and no overheating. I've since taken it on 5 long drives and its sitting at a good temp and not getting too hot. I took the old pump apart and it looks perfectly good, with no movement (by hand) on the pulley bearings.

[davidwort 0]

got any pics? what sort of state is the impeller in? some are plastic and can break or seem to corrode/chip away

are you sure it wasn't just the thermostat?, I'm assuming you changed that when fitting the new pump.

[sam2.0 10]

The thermostat had been replaced 2 months prior, but it was a little bugger to do as we left the pump and power steering pump on, so very fiddly. I figured I could have damaged it, so put a new one on the new pump as it was very straight forward.

 

I did take the old pump apart and the impeller looks fine, I'll do some photos if you want.

[sam2.0 10]

[ATTACH=CONFIG]71496[/ATTACH][ATTACH=CONFIG]71497[/ATTACH][ATTACH=CONFIG]71498[/ATTACH]

[dil 0]

is the fan connected with a plug that can only go one way? i ask as i once connected the wires incorrectly and took me ages to figure out my fan was blowing the wrong way and that was the reason why my car wouldnt cool down.

[sam2.0 10]

No, fan is 3 pin and can only go on one way. It blows over the rad from the front, not from the back!

[davidwort 0]

that impeller doesn't look like it's pressed onto the shaft all the way!?

it also looks like it's been scoring against the other half of the casing, does it actually turn at all when together!!!?

[sam2.0 10]

Didn't even think to play about with it once off the car, I was so happy I had fixed it!

 

You're right though, the scoring looks fresh and consistent that they've been rubbing. I assumed the impeller wasn't meant to go all the way on.

 

I'll have a play with it later and see if it is touching.

[davidwort 0]

think I've got a used spare at home in bits, I'll have a look at how it's assembled and worn