Does this sound like a water pump problem?

[Antsmash]

Hi guys,

I'm calling on your advice again

After replacing my heat tap last weekend with some friends. We also flushed the system. The water was quite rusty as I expected as I've done one flush before. We re-filled system, took it around block a few times and it all looked good.

Then I started having problems when I was sitting at lights etc. the temp would go up and up, and as soon as I started moving it would drop back down.

I thought the most likely option after just flushing would be an air lock, so I tried a few tricks (1.5l coke bottle) and still no luck. So I decided on Thursday to just flush it again (Because hey, it obviously wouldn't hurt).

Once again still no luck.

Today I recalled a few times over past months my temps would get high then shoot down all of a sudden whilst sitting still, so I replaced my thermostat. That still didn't fix problem, but definitely needed replacing anyway.

A friend suggested it could be my water pump, so whilst testing today I sat still, temp got up to about 112deg, I put it in nuteral and idled at 2000RPM and temp started to drop back down to 104deg-ish. I did this twice and it worked.

Any idea why this would happen after doing a flush? My friend did stupidly pop the radiator cap while car was warm (Creating a lovely fountain), maybe this helped finish off the water pump.

Thanks for the help.

 

[Sabbath']

Did you bleed the cooling system properly?

 

[Adds_05]

sounds like it still has air in the system

 

[Fletch_QLD]

Could be air flow (hot when still, cools down with movement) Check your fans?

Radiator cap ? Even new ones don't always work the best if they are cheap and nasty. The symptoms I got from a fail radiator cap was that when I pulled up after a bit of a drive, water would bubble up out of the radiator overflow. I suspected water pump on that, but it was as cheap and easy as a new radiator cap.

I don't know how to diagnose a failed water pump - unless there is water leaking out in front of the bearing.

 

[Clutchy]

id say air in the system aswell the water pump make any noise or leak ? does the pully spin pretty straight ? but the fact it started after ya had the water out of the system tell me its just got air in it.

 

[Antsmash]

Thanks for the replies guys.

I replaced the radiator cap with the exact same brand etc. as the last one when we flushed it.

No leaks from the water pump, and belt looks pretty good. I'll have a more in-depth look at the water pump today.... if it stops raining.

Fans seem to be coming on correctly. An airlock would make sense. I wonder where the airlock is? Heater works really well.

 

[ian]

hi
did you bleed the air through the bleed valve on top of the thermostat housing ?
what i have to do with mine is when its cold start the engine
, take the radiator cap off , then add water to the radiator while squeezing and letting go
the top radiator hose , coz when you squeeze it it brings the air to the top ,
also it helps if the front of the car is raised so the filler neck is higher than the thermo housing

 

[Antsmash]

Thanks Ian I'll give that a try. I noticed once when I was filling it, once car warmed up the water was going up and down in the radiator neck and then flowing over. Is this a bad sign / a sign of an airlock?

I've tried bleeder screw, and usually once car is warm there is a fairly steady stream of coolant coming out onto coil pack.

My driveway is on a bit of a slope, nothing massive though. I've also tried parking it facing down overnight to see if that would help.

 

[Antsmash]

Any other ideas guys? I tried the bottle again yesterday, bit of bubbles came out. Might try it again today. Drove it a little today, seems like it's a bit better, but might be my imagination.