2.5 overheating

Post Tue Feb 28, 2006 11:42 am

my 2.5 12valver is overheating. i have changed the thermostat, and i'm pretty sure the viscous fan is ok. theres some white steam comin out of the exhaust but the engine is runninbg smoothly and revs all the way up. i thought it might be the head gasket but i then found a water hose going from the thermostat housing to the throttle body was corroded and the actual metal pipe on the thermostat housing had broken off. i think the water from this pipe has the leaked into the throttle body thus causing the steam? does any1 have any ideas???

Post Tue Feb 28, 2006 5:41 pm

water pump ok mate?

Post Tue Feb 28, 2006 6:26 pm

not sure really. i'll check 2moz

Post Wed Mar 01, 2006 1:38 am

if this is leaking the slightest bit it will cause her to overheat.... i had this very problem, changed the pump and cured it, how ever the "white smoke" you say coming from the exhaust sounds funny similar to a gasket problem but if you have had it checked it cant be that? you noticed any drop in performance... spluttering etc...?

Post Wed Mar 01, 2006 2:28 am

If all else is fine.. I would be VERY certain its a water pump problem.. They are hard to spot some times if its a slow leak, as, the second it leaks it evaporates due to a HOT block! It can't ever harm to change the pump and its not a hard job so it would always be my first port of call after the usual thermostat etc. Make sure you get the block nicely cleaned up and all the old gasket clean off so you get a good firm seal with the new pump nd gasket! Get a new one whopped on there and see what happens, if its still not working it could be a blocked cooling line or an issue with oil cooling or lack of oil pressure causing excess friction in parts, but I think if it was anything like this you would know about it by now as it would have caused alot of other issues.

the be all and end all of my post... change the old water pump - they are notoriously unreliable. happned to my merc as well less than a month ago, new pump from a parts dealer for Ãƒ”šÃ‚£40 and an afternooons work and she is back to her usual cold running self even without a fan!

good luck - Jon

Post Wed Mar 01, 2006 6:05 pm

there is no drop in performaNCE at all so i'm a wee bit baffled. today i changed the thermostat housing and cleared all the cooling pipes. i replaced several gaskets on all the cooling parts including the throttle body (where the colling bits are) and still no luck. i think i'll change the water pump tomorrow then and we'll take it from there. thanks guys.

Post Wed Mar 01, 2006 7:27 pm

Is the car actually using coolant?]

Post Wed Mar 01, 2006 10:42 pm

the car isnt using any coolant as far as i can tell. theres no oil in the water or mayonnaise around the oil cap ( i took off the rocker cover and it was no mayo anywhere.) however, where i found water leaking into the throttle body there was mayonnaise.ive fixed that now by replacing the gasket in the place on the throttle body. after running 15mins i open the bleed screw to let out the air and there is shit loads of steam. ie its boiled water so it must be the pump right?

Post Wed Mar 01, 2006 11:09 pm

Where's the temp gauge during all this. If the car isn't using coolant once all the air is out, and it doesn't overheat, then what makes you think there is anything wrong?
White smoke is just steam condensing. It's cold and burning petrol produces loads of water.

Post Thu Mar 02, 2006 7:35 pm

hi there, the needle was in the red. however. today i changed the water pump and its fine. the problem now is the oil pressure light has come on and the car stalls at low revs... plus there wwas loads of bluish smoke comin out of the exhaust at low revs. the light comes of at high revs. what the hell is goin on?

Post Thu Mar 02, 2006 9:04 pm

Blue smoke is oil being burnt in the pistons/Combustion chamber, and the light indicates low oil pressure.

Post Thu Mar 02, 2006 10:33 pm

kam-325i wrote:Blue smoke is oil being burnt in the pistons/Combustion chamber, and the light indicates low oil pressure.

This is not good. You may be looking for a nice new engine to attach your new water pump to.
If you are very lucky, you may have routed the wire from the oil pressure switch wrongly after changing the punp (it goes across the timing belt cover), and worn through the wire so that it is shorting to the engine and turning the light on.
Doesn't explain the blue oil smoke though.

Post Thu Mar 02, 2006 11:34 pm

uh oh. the wire isnt shorting as i checked it and it seems fine. i found a couple of rocker cover bolts had broked off, thus the cover is a little loose. could this account for the loss of oil pressure? the oil seems really smokey when i open the oil cap, thanks for your advice here, i have a bad feeling in my toes about this one though. only got 113000miles on it as well.