matth76 1 Posted June 3, 2006 Report Share Posted June 3, 2006 HiToday was driving down the dual carriageway in my mark3 golf vr6 and my engine water temp hit max and some steam was coming from the bonnet..the red light on the dash board came on (the one on the very left which I assume is the water temp light which looks like a thermometer). Pulled into a layby straight away. I opened the bonnet and there was no water in the antifreeze tank. There was a strange metal grating noise too if I tried to move the car a foot or two. No noise at all if I revved the engine a bit while stationary. The oil temp had risen to 118c which I was told by the Phirm that this was ok and well within limits.Car had no water leaks. The water had escaped as steam through the water tank.Had the car towed to The Phirm who were excellent and diagnosed straight away that it was the thermostat that had caused all this (pipe to radiator was hot, one underneath was cold - indicating it was the thermostat). Will my engine have suffered any damage? It all sounds fine when it is revved stationary even to high revs. Haven't tried driving it or moving it so not sure what the strange metal grating noise was...the Phirm will carry out checks next week.What could this strange metal grating noise have been?Just had my car rolling roaded today at stealth (207bhp). Is it likely this figure will be reduced after today?Thanks for any help. Link to post Share on other sites
matth76 1 Posted June 3, 2006 Author Report Share Posted June 3, 2006 How quick or easy is it for The Phirm to do a compression test? Will that be the sure tell tale test to see if my engine has suffered any damage even slight damage? Link to post Share on other sites
jb9999 0 Posted June 3, 2006 Report Share Posted June 3, 2006 That just does not compute, Matt. The lower radiator pipe coming from the radiator to the engine is supposed to be a lot cooler than the top one and does not indicate a faulty thermostat, but suggests a healthy one.Can you see where the coolant has come from, like the expansion tank overflow? The light that come on is your coolant level indicator, not the temperature, as soon as the coolant gets below the prongs built into header tank, the light comes on. If the top pipe was cold that would suggest a faulty thermostat as it is not opening when it should. The grating metal noise sounds worrying? Link to post Share on other sites
matth76 1 Posted June 3, 2006 Author Report Share Posted June 3, 2006 Thanks for your reply. I couldn't see where the coolant escaped from exactly. I assume from the coolant tank itself through the lid 'hole'..certainly was around the area of the coolant tank. The strange metal grating noise seemed to come from the passenger side wheel on the left hand side of the car. The oil temp didn't go above 118c. Will this indicate that my engine itself 'should' be ok? Will a compression / leak down / block test eliminate the possibility of any problems?Could the strange noise be the water pump running dry? Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 I don't think the noise you heard would be from the water pump, unles you drove it for about 200 miles after the coolant level light come on. If the coolant has come from the overflow, the inner wing and chassis leg directly underneath the expansion tank will be soaking with coolant. Plus, if the noise was from the water pump,it would be all the time, not just when you move the car.Unless you can see any obvious signs of coolant leakage, I'd get it pressure tested.Plus ,the water pump is on the drivers side, not the passengers side. Link to post Share on other sites
matth76 1 Posted June 4, 2006 Author Report Share Posted June 4, 2006 Thanks. When you say pressure tested do you mean have a compression test? The water pressure itself was tested and all is fine...no leaks at all even under pressure. It must have escaped when it became too hot through the expansion hole. There was only water under the tank and that area only.It is odd the noise only happened when I tried moving the car... not when revving it when stationary. Link to post Share on other sites
VR6Pete 1,455 Posted June 4, 2006 Report Share Posted June 4, 2006 Lets hope you have no warped your head... Link to post Share on other sites
matth76 1 Posted June 4, 2006 Author Report Share Posted June 4, 2006 How can I tell if I have warped my head or not... will a compression test show up this?If my head is warped what is the remedy...a new head gasket? Or more?!Thanks again for any help. Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 I meant the cooling system pressure tested Matt,sorry, but like you said above it's already been done. It may just be that you have not had enough antifreeze in your system and it just boiled over. I always have at least50% antifreeze in.If the head is warped it would have to come off and be skimmed, which would mean a new head gasket . Not quite sure what the symptoms would be, but a cylinder compression test should tell if there is anything wrong or not, and should not take longer than half an hour. Link to post Share on other sites
mk3anni 0 Posted June 4, 2006 Report Share Posted June 4, 2006 .The lower radiator pipe coming from the radiator to the engine is supposed to be a lot cooler than the top one and does not indicate a faulty thermostat' date=' but suggests a healthy one.[/quote']Dunno where u got that idea. The radiator doesn't cool the water so much that the top pipe is boiling hot and the bottom is cold to the touch, the fact that the pipes where boiling hot at the top and cold at the bottom proves it is the thrmostat, because the water isn't getting into the rad.Matt, for gods sake will you stop worrying. The head wont be warped, the gasket should be fine, cos you pulled over, would take a lot of abuse to damage the head.Your such a woman some times!!!! Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 If it was the thermostat, it would not be opening to let the hot coolant from the engine (top hose) to the radiator. Therefore the top hose would not be hot. The fact that the top hose was hot indicates that the thermostat was open and letting coolant flow from the engine to the radiator. The thermostat is in the thermostat housing, ON THE ENGINE, NOT ON THE RADIATOR.Also if the bottom hose was the same temperature as the top one,what is the point of having a radiator???? Link to post Share on other sites
mk3anni 0 Posted June 4, 2006 Report Share Posted June 4, 2006 NopeDon't agree.Your making out that the rad drops the temp so considerbaly that the pipes are cold to touch, which is bollocks.I know full well where the thermostat is thanks, however common sense tells me that the little bit of metal the thermostat is made of is incapable of stopping heat, therefor causeing the top pipe to get very hot and the bottom pipe to stay cold BECAUSE THE WATER ISN'T FLOWING <-see i can use caps too.How about we see what the answer is when the phirm have finished with it eh. Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 If you had read my post correctly, I did not say that the bottom hose should be cold, I said it should be cooler than the top one.The thermostat is just a valve that opens when the coolant in the engine gets to a certain temperature, allowing the coolant to flow to the radiator from the engine (via the top hose, heat rises??). The thermostat is not to `stop heat` as you put it, it is to control the temperature of the coolant in the system. Feel free to pm me if you want me to explain in greater detail the basic principles of the cooling system. :-d Link to post Share on other sites
mk3anni 0 Posted June 4, 2006 Report Share Posted June 4, 2006 How about you read my post properly, just a thought. Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 I did and it still doesn't make sense.The top hose only gets as hot as the coolant running through it. Link to post Share on other sites
VR6Rich 3 Posted June 4, 2006 Report Share Posted June 4, 2006 I think what mk3anni is trying to say is that if the thermostat has jammed shut (faulty) this would stop the coolant flowing. Because of this the coolant on the engine side of the thermostat rises in temperature. This heat is transferred through the metal of the thermostat to the coolant on the radiator side of the thermostat. Thus giving a hot pipe at the top and a cooler pipe (due to lack of flow) at the bottom. Link to post Share on other sites
mk3anni 0 Posted June 4, 2006 Report Share Posted June 4, 2006 Yup, thats my point rich!! Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 I can see your point now, not sure if you can see mine. If the thermostat had stuck closed, would the bottom hose not get hot eventually as well? Seeing as there was no flow through the radiator the coolant in the whole system is going to get very hot.Plus the heat transference from the thermostat would probably be enough to warm the coolant in the top hose, but it will be no where near the temperature it gets when practically boiling hot 90degrees coolant is being pumped through it. There's another thing, pressure. Link to post Share on other sites
VR6Rich 3 Posted June 4, 2006 Report Share Posted June 4, 2006 Yeah true, but would take longer for the heat to travel to the bottom hose than the top. Link to post Share on other sites
matth76 1 Posted June 4, 2006 Author Report Share Posted June 4, 2006 Thanks guys. Ok guys...another question - worst case scenario, say my head gasket needs to be done...now or in the future, how much extra (on top of the labour and parts to do the head gasket) would it cost "roughly" to fit a "big valve head", and everything needed? Got to try and make the best out of a bad situation! Anyone here know how much extra power a big valve head might produce? Or would a "gas flowed head" be better value for money..I know this is a lot cheaper, but how much power would this produce?Cheers guys Link to post Share on other sites
jb9999 0 Posted June 4, 2006 Report Share Posted June 4, 2006 Don't think it will come to that Matt. You pulled over as soon as it overheated so the engine should be fine. And to save another argument with MK3Anni, get a gas flowed, big valve head!!! Link to post Share on other sites
mk3anni 0 Posted June 5, 2006 Report Share Posted June 5, 2006 Don't think it will come to that Matt. You pulled over as soon as it overheated so the engine should be fine. And to save another argument with MK3Anni' date=' get a gas flowed, big valve head!!![/quote']I agree, matt your worrying too much. Worst comes to the worst get a flowed and ported big valve head (i think thats all the options!!) but i warn you there not cheap! Link to post Share on other sites
matth76 1 Posted June 5, 2006 Author Report Share Posted June 5, 2006 All sorted. Had the thermostat changed and all seems fine now. Still pulls as hard as hell all 207bhp. Glad to have the car back! Also got The Phirm's quick shift for my gearbox. Certainly an improvement over the long throw on the stock gear box. Great thanks to the phirm for diagnosing and fixing it all. Only two days ago I thought my engine was f*cked! Link to post Share on other sites
mk3anni 0 Posted June 5, 2006 Report Share Posted June 5, 2006 Yeah u did, look on your face when u pulled in was a picture.BTW Jimbo, that means i was right, if you want me to explain the cooling system to you, PM me. Link to post Share on other sites
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