Water Pump?

[shakermaker]

I mentioned in a previous thread that my TF 160 has been loosing a small amount of coolant, not too much just needed keeping an eye on. There was mayo on the dipstick but the car has only been used for short runs over the Winter. Some weeks I didn't use it at all.

I let my local garage have a look at it last week to see if there was a leak of some sort. They've done work on the car before eg changed the cam belts a year ago as well as the water pump, and I trust them to do a good job. There was no evidence of a leak, so they wondered if it was early signs of the dreaded HGF. They suggested using K-seal as a temporary measure to postpone what is going to be a hefty bill.

After driving the car home from the garage, about 4 miles the water temp gauge was swinging from it's normal rock steady position just below half way to up to maximum. At that point panic set in.
I thought at first it was an air lock, but having bled the system myself and taken it back to the garage for them to do it, it doesn't appear to be the problem. At the moment the water temp gauge fluctuates with road speed. If I put my foot down a bit, it shoots up if I ease off or if I'm going down hill it goes back to normal.

Yesterday, I removed the radiator thinking it was blocked, but after flushing it out, I could see it wasn't that. I have noticed something odd about the coolant pipes as they emerge from under the floor of the car. Looking at them from under the bonnet, the right hand one, which goes to the bottom of the radiator, is hot as you would expect, but the left hand one going to the top of the radiator is hardly warm. This seems to suggest to me that the water pump has failed, or could the K-seal have blocked the thermostat perhaps. Is it possible for the Pressure Release Valve to fail or become blocked?
Anyone have any ideas?

[Mike H]

The fact it is/was losing coolant is never a good sign, and one that needs to be investigated! I'd have to say that if the water pump was replaced a year ago when the cambelt was done, then the chances of that failing are slim (but not totally impossible).

You don't mention whether the head gasket has ever been replaced?

You've obviously had the radiator out to check, but are there any other signs of a leak? Have you stood the car on eg newspaper to check? Are all the hoses and underbody pipes sound? Have you changed the cap on the expansion bottle? Is there any evidence of mayo on the dipstick after a long(er) run?

Have to say that K-seal and the K series is not a good combination, and I would personally worry about a garage that suggested that.

From the above, my suggestions would be, depending on there bring no mayo on the dipstick after a run, to change the pressure cap and then double check for leaks everywhere, standing the car on paper as necessary. If it is still losing coolant AND there is mayo on the dipstick after a long run, then unfortunately it doesn't bode well

[shakermaker]

Thanks for that Mike. The head gasket has not been replaced to my knowledge, but I've only had the car 2 1/2 years. I have changed the expansion bottle cap. I agree that using K-seal was not a smart move on the part of the garage, I only found out about the problems it can cause after the event.

Having thought about it more I'm fairly convinced that the overheating is caused by a blockage in the cooling system probably exasperated by the K-seal. I'm going to have a look at the PRV and the thermostat this week because as I said the hose going to the bottom of the radiator is hot, whilst the one from the top of the radiator is cool. To me this indicates there is no flow of coolant through the radiator back to the engine.