I posted on TwinTurbo.net about my coolant loss problem and some of the guys on there seem to think that a cacked thermostat could be the problem.

 

Can any of you EXPERTS enlighten me on the symptoms or problems you would experience if your thermostat was Dicky Davis or KO'd?

 

TIA

timmy what kinda symptoms u gettin, just a loss of coolant or is yer car overheating??

 

 

john crisp

Losing coolant mate, shut the car off after a run and a pool of water appears underneath the expansion tank.

 

Not overheating but if she loses that much coolant that does start happening. Heater on full stops it getting to the point that damage to the engine is likely. I have a Techtom so I can monitor the temp a degree at a time before the sh1te stock gauge even wakes up to what's about to happen.

 

Sniffer test done by the Yellow Erics (AA) but no signs of zorst gases in the coolant.

 

If I boot the car you can smell the coolant if you got a window open.

 

Heater matrix replaced a while back, new rad at engine rebuild a while back.

Once the car has been running for a while check to see if you can hear the coolant bubbling. If so feel the two pipes connected to the resevoir, they should both be hot. If one of them is cool then it's a tell tale sign that the thermo has ceased.

 

My Mate had the same problem last month with the BMW I sold him.

Stu,

 

Cheers, I thought there was only one pipe to the expansion tank?

Timmy

I am not a 300 expert but a cracked thermostat sounds a bit dodgy to me, if it was cracked to me that would mean like in stuck open, it would cause the car not to heat up properly like as in poor heaters etc,or do they mean cracked causing the thermos to stay shut, any history of your car having a water pump fitted or anything like that . Does your radiator have any cold spots on it like its maybee blocked after the engine is warmed up.

 

HTH

 

John Crisp

Not sure about the thermostat mate, only change really was the aftermarket autobox cooler. It's mounted dead centre whereas I've noticed some peoples are offset to the right as you're looking at the front of the car.

 

Car reaches normal running temp under normal conditions and only starts to rocket skywards once the coolant gets low and the car is stopped on tickover.

Sorry, forgot to mention that the viscous fan went west and was replaced so could a knackered viscous fan upset the water pump in anyway?

Had a new rad cap anytime recently Tim?

 

Classic radcap signs - you stop, the water heats up locally, the pressure in the system rises and the rad cap (prematurely) vents into the overflow tank (it's not really an expansion tank, hence only one, small, low pressure pipe).

 

Once it's done it enough times to fill the overflow tank up to where the neck meets the bottle, you get a little puddle under the tank..

 

How do I know? Coz mine does the same :D

 

Empty the tank (if you can be arsed) and see if it slowly fills up - if it does, radcap (presuming the HG is intact, which the sniffer test indicates in your case).

 

Enjoy..

 

PS, apologies if I've missed out some blindingly obvious bit of info, or if you'd already told me at some point in the past that you'd had a new rad cap.. Been on the rum all night - memory is blitzed :D

Cheers bud and stay off the Rum! LOL :D

 

Yep had a new Blitz rad cap which IMO didn't seem to fit snugly enough so I bought a new Nelson jobby but still it drinks coolant.

 

I bought a new expansion tank a while back but haven't fitted it. You're right though, I had the wheel arch liner off a while back and as you correctly pointed out there is a whole on the neck. At first I thought that wasn't right but after getting the new one it is supposed to be like that.

Timmy ......

Most garages should be able to do a pressure check on your coolant system to identify any leaks in your system.....

If you have no visible leaks ( other than underneath the expansion tank ) it is possible your water pump is on its way (not circulating the coolant sufficient enough ) causing the coolant to exit via the expansion tank ......

Dave

Cheers mate, all things I wanna get sorted before the summer and the shows. New water pump and a new thermostat even if it's not west.

I might be barking up the wrong tree but its not just air in the system is it? Mine used to leave a small puddle and once a big puddle and a very high temp guage, but after filling it back up with coolant and doing the air bleeding thing a couple of times the problem was cured.

 

At least this method costs nothing to try.

I've tried bleeding the system but like you say mate it might be a good idea to start from scratch and try flushing the system and refilling.

Timbo,

 

 

Don't know if it is like what I had a pool of water dripping from the front midlle of engine, fixed mine, then fixed bruce wards after a certain mechanic on here did a cambelt change and didn't change these hoses!!

 

 

There are two hoses going into the block right by the thermostat, change them and the thermostat at the same time!

 

Should all cost no more than £20 and an hours time, if you do it yourself give me a ring and I will talk you through it!

 

Mark

Have you checked the hose from the rad to the expansion tank? It may have come off the expansion tank and instead of water going in there it just dumps on the floor - worth a check ;)

 

CheerZ,

 

Andy

A simple check to prove the cooling system is pressurising properly is to squeeze the top rad hose when the engine is good and warm. If it is soft then you've no pressure and the water will boil at lower temp also leading to local vapour lock in the heads and eventual overheating.

 

It should be well burny burny and firm. Watch you dont get the tips of your fingers knocked off with the fan if the engine is still running!

 

Isnt the Z system supposed to suck some water back from the expansion tank once cooled down and if the exansion tank is overfilled it will always dump the excess on the floor.

Andy Duff noticed that my top hose was a tad limp at the GPS meet ages ago.

 

Andy, I've had the expansion tank out and the hose is connected mate.

Think you might have a leak somewheres or your rad cap or the surface in the rad filler for the seal is a bad one stopping it making a good seal. Look for marks or cracks on the cap seal.

 

Also like someone else may have pointed out look at those short hoses behind and below the top rad hose conn on the engine. One to each cylinder head. I had a leak from one and you can only see it by using your partners make-up type mirror and a torch - you get powder everywhere! She wont like this. The water would eventually drip off the sump somewhere and you could only catch it doing it when hot after just being filled up with water. If you left it alone it wouldnt leak much more because the water level was now down below it and the pressure could not get up enough to start it again. You then can then get local boiling yet a soft top hose because there's no pressure. Seems these little hoses can go every 3 years. They are a bit awkward to change but I found you can do it without taking the fan off if you dont have too big hands! Pootling around in this weather wont hurt it but a roasting on the motorway might.

 

Think you should top the rad right up with water then idle it till hot and look underneath for the drips then search for the source.

 

The top hose should suddenly get hot as the stat opens then begin to firm up then only go soft once it has started pushing the water out. If it is the rad cap that has a bad seal then the water will be going to the expansion tank almost immediately you start up.

Hope you find the problem

OUr car did this int he summer, wont do it any more though, I can leave it idling for over half an hour, the temp will stay spot on and not a drop of water on the floor. The water level has not dropped at all either, wierd.

Another easy possibility - check the tightness of the bottom hose clamp on the radiator. The trouble is the end tanks of the rad are plastic so you're always wary of tightening it too much - I have seen leaks here before. Lets hope its this simple :)

 

CheerZ,

 

Andy