heaters suddenly went ice cold then car overheated help
 

hiya al, i have got a 1999 uk turbo 2000. whilst normal driving my check engine light started randomly flashing on and off in a total random order. i had no power loss and it would only come on after id been driving for a fair while. then a few days later i was driving around and my heaters went from being red hot to ice cold, i thought there was no water so i checked and it was full of water, i have since changed my thermostat, and checked that the radiator isnt blocked, however when the car gets up to temperature the bottom radiator hose remains cold yet the top radiator hose is hot as is the thin hose that comes out the top of the radiator. the car does not smoke and there is no bubbles in the header what could this be??

Could be a Failed/Failing water pump!

how can i check if it is the water pump?? and is it a hard/expensive job??

To be honest i am pretty sure the only way to check if any of the fins have snapped of the impeller inside the pump is to remove it and have a look, And yes it is a pain in the arse of a job so I would immagine it would be pretty expensive! I take it you have checked to make sure you have no oil in the water? (Head gaskets).

you could check the water pump by removinig a hose and seeing if the water pump pushes the warter out of the block . the best way to check it would be to remove it but this would involve removing the timing belt you would be looking for broken propellors also the propellors shuld be fixted to the pully . you could try flushing your cooling system out with tfr or some thing like daz hand wash put a cup in at a time and run the engine up to temp then drop the fluid you do this till the coolant comes out clean .it sounds like your heater matrix is blocked

hiya, i have checked for all usuall headgasket issues, and they are all fine. i have drained the coolant sytem out 3 timres today, and refilled and bled the airlock out. i have once again got hot air so i dont think my matrix can be blocked. i will take the hose off and check the water pump tomorow. also is it normal for water to flow back into the header tank through the small hose that join the neck of the header??

water pump about £55-60 and you will need a new timing belt about £40-50, it's not to hard to do but if your not shore get someone else to do it.

yes it is normal for for warter to flow through the small pipe back into the headder tank . Eventhough you have flushed your system through with warter there may be muck still in there . The warter may of come out clear but daz or something like will lift all the crap off and clean your cooling system .

Hi Skinner, What sort of flow rate or ammount of coolant would you expect to see coming out if he removed a pipe if the pump was functioning proper? Not trying to be arsey was just wondering incase i ever need to do it!! :wonder:

It wont push it out that fast and you need to make sure you have warter in your block .like you said the best way is to visualy check it you could not tell if 1 fin was snaped or some fins were corroded . It sounds like his pump is working to me as his heater is getting hot now.

BigTazzsi...Hello mate, If it was my car I would have the pump of to check it because if any of the fins have snapped of or corroded then the pump may have enough efficiency to pump the coolant to the heater matrix but under some "Spirited" driving may not be enough to stop over heating issues and that could be a whole differant world of pain. IMHO!

hiya guys, ive been driving the car today, and touch wood it has been fine, heaters have been red hot temp hasnt risen, and ive been fairly spirited too. however... the bootom radiator hose is still cold! yet the one at the top is hot. is this normal?? i put a hosepipe in the radiator this morning in the top and blasted it and the water came out the bottom outlet fine so im guessing that isnt blocked. help?!

when its warm feel the radiator with your hands - make sure the rad is hot every where

sounds to me like a/ water pump is knackered or b/ the rad is blocked (it doesnt matter if water comes out the bottom pipe it still can be blocked

the bottom hose will not get as hot as the top hose. its normally just warm

to me it sounds like an airlock or the stat aint working. Check the thermostat - remove bottom hose, undo 2 bolts and slide off the housing. You can then flick out the stat and test in hot water. just be careful of the stat gasket when you remove it

hiya the stat is fine already checked it, the radiator is cold on the one side i have got another today so will try that tomorow.

my car had the same probs bud, no bubbles in header, cold radiator and bottom hose but a hot top hose. changed radiator, water pump, thermostat and several ropey looking hoses and guess what?.........same problem!
engine is now out on a stand and from what I can see on the drivers side head the head gasket was passing.

I know its not the news you want to hear but thats how mine started 6 months ago and gradually got worse and started using coolant and the fans would come on even thought the radiator was cold.

sorry yes, just re read and you do mention that you changed the stat :)

The symptoms do sound like an airlock because or the cold half of the radiator. Thats why the temp of the heaters will change as you describe and the water in the block gets hot and overheats, whilst the heater matrix goes cold due to none of the hot water passing through/ being replaced with air. That said its why the air is in there in the first place. If you had just changed the fluid and it happened after you would think its airlock related due to poor bleeding. But if its happened randomly then there is a good chance the air is getting forced in - through the Head gaskets passing through a combustion chamber and heater gallery.

The easiest way is to take it to a garage and have them do a sniffer test to check for gases in the header tank. This should confim either way the presence of the gases and ultimately the way forward. Just be sure to act quickly though as overheating will damage the heads and therefore increase the repair bill. If you seach through posts you seem to find others having the HG replacement done and then the bottom end going a short while after. Get it checked asap and limit damage.

Hope it works out for you mate :thumb:

Not seen a water pump impeller fail on these cars yet. You should always refill the coolant system using the pipe that feeds the turbo from the header tank, or you’re almost guaranteed an air lock of some description.

Basic checks for head gasket, remove the header tank cap when first starting the car and look for multiple small bubbles when revving the engine. You can also detach the over flow tank water pipe and run this to your windscreen area so it’s visible. Take the car for a drive and when on boost if you see water escaping from the pipe, it suggests excess pressure in the coolant system which can imply head gasket. I would refill as above fist.

The bottom hose should be cooler than the top hose this indicates the radiator is doing its job and the cooler coolant is ready to go back into the engine.Dont forget if you have been driving fast there will of been a lot or air flowing through the rad and it has been cold today. However there should be no cold spots on the radiator this would indicate a air lock or a blockage.I would try flush the system out with tfr (the stuff you use for steam cleaners)it will lift the dirt out of the cooling system i have have to do this before.The car could of had oil in the warter before and still be there were you cant see.I dont think you have a head gasket problem but a air lock could lead to one.you could do a compression check on your engine some one close may be able to lend you one.