Overheating - Water Pump Or Not?

Sarah

My car started overheating a few days ago so I asked my usual mechanic to come and do a pressure test and possibly change the thermostat if there weren't any leaks. It hasn't been losing coolant whilst stood on the drive, the temperature just kept going up until it got to boiling point just as I pulled up on the drive!

I'm pretty sure it's not the head gasket, having owned one of those awful Freelanders with the K series engine and lived in fear of of the head gasket going, so know a little about what to look out for.

The mechanic did a pressure test and there were no leaks, the fan is coming on, but there is no heat from the heater inside the car. His mate said that the thermostat was opening, but I didn't see it myself and as the mechanic himself was revving the engine and not actually looking at it I'm not sure I can trust the theory that it's the water pump.

He's quoted me £180 labour to replace the water pump but I know the thermostat would be alot cheaper. The engine also smokes and he previously put some stuff in with the oil that reduced it whilst under normal driving, but it does smoke badly when revved in neutral. Apparently this could be stem seals which is another expensive job and I'm not putting a new engine in it because I can't afford the labour involved.

I am reluctant to spend any money on the car if the engine could pack up at any moment because of the smoking so I'm not sure what to do! I have limited funds but don't want to gamble it on a water pump if it's the thermostat.

Two people have told my husband that it's unusual for a water pump to pack up but the mechanic said they were known for it, so I'm very confused. It's only done 87k which is not alot for a car that age.

Is there a sure way of telling which it is without taking the engine apart? Sorry for the rambling!

IDI_AMIN

Why not get another opinion from another mechanic and get a new thermostat see how it goes

Sarah

Because then I will have to pay more labour costs and if it's not that I've wasted money on parts and labour. Gambling doesn't usually go very well for me.:LOL:

Sarah

Saying that, I'd rather gamble on a thermostat than a water pump.

IDI_AMIN

Sarah said:
Because then I will have to pay more labour costs and if it's not that I've wasted money on parts and labour. Gambling doesn't usually go very well for me.:LOL:

Thats because you have a bad choice of mechanic possibly taking advantage of you because you are the fairer sex to me it sounds like the thermostat if it was water pump you would lose a lot of water also why not do a google search "symptoms of a faulty water pump " then you will realize it is more than likely a faulty thermostat it was the mechanics mate and not the mechanic who told you it is the water pump if you cant get heat in your car i would put my money on a thermostat and i don't really like gambling myself if it is then you buy part yourself from local auto shop and get a mechanic to fit it for you this will keep costs down

Sarah

Thanks. It's not the mechanic I don't trust, I've had him out before to do the brakes and he said there's nothing wrong with the brakes. It turned out to be a faulty sensor which was covered by Kwik-Fit's guarantee so they did it for free and he got nothing out of it. I don't know how knowledgeable his mate with him is or if he's trustworthy, he could have been telling the mechanic the thermostat was ok just so he could get them some work. Can you see the thermostat working just by looking at the engine? I'll take it out to get some petrol and see if the heater works.

IDI_AMIN

Its attached to a water hose so you need to take it off and test it in hot water to find if its opening or not if they never done this then you cant trust the mates opinion plus the age of the car could also suggest it needs replacing whatever year it is if its never been done before. thick hose runs up right hand side of engine to a metal housing part this is where thermostat is

astra22bertoneauto

Ive had a few of these engines now and ive never had a water pump go. Engine smoking badly is more likely piston rings when revving/driving. Stem seals symptoms normally give off a little bit of smoke when you start the car.

Id gamble on a thermostat as its a 10 min job to put in then refill with coolant. worn thermostats open earlier/later than they are supposed to and/or jam open/shut.

No heat in the car could be 1 of 3 things; air lock, cable popped off the flap behind the centre console or heater matrix faulty. 1st 2 options are easily sorted and more likely.

Hope that helps

Sarah

Thanks, that's very helpful, they didn't take the thermostat out to test it. There is no heat in the car. Is the engine likely to give up if the piston rings or stem seals have gone?

vocky

if the thermostat was faulty the heater would still work, because the heater system is actually the thermostat bypass system - thus it flows when the thermostat is closed or open.

It is rare but I have heard of the water pump impellor shearing off on the z22se engine, a quick way to tell would be to see if the coolant bottle return pipe (small 10mm diameter black hose) has flow or not (when the engine is hot it would flow quite fast if the thermostat was closed)

Sarah

How do I tell if it has flow? When the temperature was up to 100 degrees the other day the water was bubbling in the coolant bottle.

MikeS

run the car up to temperature and check all the hoses and radiator

physically go round touching the pipes and coolant expansion

get back to us !

secondly has the heater worked since you bought the car ?
does the fans kick in when you hit 100C ?

Sarah

Yes the heater worked fine until it overheated, not sure if that's a coincidence and the fan does kick in.

Sarah

The pipe on the left is hot, the one on the right isn't. That's at about 95c, it wouldn't go up to 100 or above running on the drive.

MikeS

way to much coolant in there also

should only be half full

make sure it is half full when cold

wondering if you got the wrong stat installed as you can get some cheap stats that dont work correctly

when did you notice engine was overheating, before or after the heater stopped working ?

if it was overheating then it would go over 100c all day long and not come down unless the fan was kicking in, stats on z22se stats open at 92c to make sure engine is running at optimum temperature, so around 90c is correct temp and the engine should not really go below 85c or 95c when actually driving normally, traffic is another matter !

I seen cars overheat as a result of a garage fitting the ht leads incorrectly, causing the wrong firing order and subsequent lean condition

head gaskets don't go on these engines, i seen faulty water pumps on this engine pissing coolant out when there was a pressure build up, also seen em leak oil like a goodun

I never heard of one failing though

Matt

As above, there is way too much coolant in there. There is a mark on the bottle with should say "cold" or "kalt" with a line about it. That is where the coolant level should be when the engine is cold and on a level road.

astra22bertoneauto

MikeS said:
way to much coolant in there also

if it was overheating then it would go over 100c all day long and not come down unless the fan was kicking in, stats on z22se stats open at 92c to make sure engine is running at optimum temperature, so around 90c is correct temp and the engine should not really go below 85c or 95c when actually driving normally, traffic is another matter !

I bought a genuine Vx stat recently with 82 stamped on it and thats when it opened. Are Vx using cool running stats now?

Matt

astra22bertoneauto said:
I bought a genuine Vx stat recently with 82 stamped on it and thats when it opened. Are Vx using cool running stats now?

From what I can tell, they are. All the stats they sell seem to be the lower temperature ones now.

MikeS

def cool running ones 🙂

remember swapping mine over to a 92c and it sat just under 90c where as before with old stat it would not go above 82c but the gunk was a nightmare in the winter

if i am not mistaken at vauxhall do you not have to buy the whole thermostat housing ?

Sarah

The coolant level was only half full when cold, it expanded when the temperature went up. The heater was working fine until the engine started overheating, I didn't even realise it had stopped getting warm, the mechanic noticed it was cold when he came out.
I didn't drive it long enough to get it up to 100 or in the red today, but usually it doesn't go above the middle. It went up rapidly when I had done a few miles the other day and I wasn't sitting in traffic. It didn't even go anywhere near that in the summer.