HELP - Overheating

[smellypaddler]

I got my car back from the mechanics after it had a 2nd hand motor dropped in and then within a couple of days I had a new radiator put in as well.

The first day I got it back it seriously overheated. Also went all surgy (clutch in revs up). So I took it back and the mechanic had it for a week and said he couldn't find anything wrong with it and if it overheated once it should overheat everytime I drove it.

So I took it out for its first drive yesterday and guess what? Yep, overheating again. This time the guage only got up to about 2mm before the too hot indicators but that was enough for me to pull over and let it cool down. (didn't surge though)

I also started it up this morning and the revs were at about 1500 until I started moving and then they settled right down to normal.

Does anyone have any ideas on what could be causing the overheating 'cos my mechanic is stumped?

[HotFourOk]

Have you set the timing correctly? Incorrect settings may cause surging like things and also cause it to overheat... just a thought

[murcod]

Have you checked the coolant level in the radiator? Sounds like there may have been air in the system and the air bypass valve wasn't working properly- that will cause the revs to surge at idle.

Perhaps the thermostat is jammed or sticking too? Get a genuine one if you replace- see my other post on my overheating probs for details.

[drewe]

Mine is doing the same thing - also just a new motor 2 weekends ago....

Drove it around a bit, has settled down a lot, but still getting hot - just not WAY hot.

Timing is out a little, but fridn said the water temp sensor to the ECU may not be reading right, causing the mixtures to be wrong, etc - hence surging and such. Checking this weekend.....

[murcod]

Make sure your vacuum advance is working and ignition timing is set correctly- running retarded timing will cause overheating too.

[chev28]

could somehow be leaning out? are there any inlet gasket leaks? these will cause intermittent surges

[tangwyn]

http://www.warfs.org/content/view/69/63/

[murcod]

http://www.warfs.org/content/view/69/63/

Jeez, just do the job properly in the first place!?

After changing coolant fill the radiator and leave the cap off; start the engine and idle it until the temp gauge is approaching the normal area, topping up as the level drops. An occasional spurt with the accelerator cable will help work any air out of the system. When the temp gauge is up to normal the thermostat will be open and all the air should be out. Replace the cap carefully (radiator and coolant will be HOT) and the job's done. Make sure the overflow bottle is up to the correct level after finishing.

Also make sure the heater control is in the hottest position so the coolant can get through the heater core when doing all this (and when draining it out too )

Finally, do it on level ground or with the nose of the vehicle uphill to assist with the air bleeding out.

Use distilled water and remember more glycol = less cooling ability.

[smellypaddler]

Thanks for all your help guys. I have spoken to the mechanic and he reckons he has tried most of the options suggested. As the car still isn't right he is going to just drop in a new radiator and see if that fixes the problem. Problem is I haven't driven the car for 3 days and when I went to get in this morning I noticed a nice fresh patch of oil under the car. One good thing leads to another