2000 VT SERIES 2 Problems with cooling system

**dope505069** · 22-05-2010, 05:12 PM

Hi Guys I have a rec urring problem with my cooling system at first my radiator and heater tap were leaking. I replaced them then it ran fine for a while.
Then couple of months later my engine was overheating while stationary (all fans working fine). So I changed the thermostat all great now.
Then two months later it has starting overheating again while stationary (all fans still working). But the thing I have noticed is I can watch the temperature gauge go up to 3 quarters of the way - full (beeping warning hot) while stationary and and soon as i rev the engine a bit to at least 3000 rpm the temperature gauge goes back down to under half again and i just keep doing it every time it heats right up i hit the accelerator for a bit and it goes down again at the traffic lights I have been doing this for a while but dont want to have to do it all the time.
From my experience I would say that it is the thermostat cause when I accelerate it opens up well I think it is but without accelerating it wont can this happen ?
How can it be the thermostat if i just changed it can they go so quick and can they open from acceleration but not heat?
I have read the thread started by Timborooni Using coolant - thermostat probs? and I do have a 135 psi recovery type cap.
Your help would be greatly appreciated any ideas anyone ?
Thanks in advance
dope
(I think my brains overheating)

**stockyvrcalais** · 22-05-2010, 05:28 PM

hmmmm i have a sneaking suspition, your water pump is buggered....correct me if im wrong anyone.

**dope505069** · 22-05-2010, 05:31 PM

Yeah well I was hoping it wasn't as to me its the most expensive thing to replace other than the heater core as i cant replace it myself but why does it cool down when i accelerate?

**stockyvrcalais** · 22-05-2010, 05:35 PM

its prob full of gunk so on idle its not letting much water through, and on acceleration with the higher revs it allows more water through, they are not expensive, have a look on ebay and not too hard to fit

**dope505069** · 22-05-2010, 05:37 PM

The thing what has always got me was the drive belt im not scared of changing the pump itself.

**dope505069** · 22-05-2010, 05:45 PM

Yeah I just found a fairly cheap one on ebay thanks for the up have u got any idea how to do the drive belt i know your supposed to mark position before taking off but thats all i know. Holden VN VP VR VS VT VX VU VY V6 Commodore Water Pump - eBay Other, Cooling Systems, Car Parts, Accessories, Cars, Bikes, Boats. (end time 19-Jun-10 07:55:50 AEST)

**stockyvrcalais** · 22-05-2010, 05:46 PM

easy, just take a pic with your phone or something, even do a quick sketch prior to removing, i know those drive belts can be a bugger lol

**stockyvrcalais** · 22-05-2010, 05:50 PM

drive belt has an idler pulley somewhere on the upper part of the engine (cant remember exactly on the v6's) you just need to get a socket onto it and lever it either right or left (you will know because you will see the belt go loose) then basically just remove the belt

**stockyvrcalais** · 22-05-2010, 05:51 PM

ps. im not saying your water pump is stuffed, but its a possibility

**dope505069** · 22-05-2010, 05:53 PM

Thanks for your help stocky If it only costs me 40 bucks and 3 hours of stress I will be very happy better than $300 at a rort mechanic.

**dope505069** · 22-05-2010, 05:56 PM

Yeah I understand that I will see what other ppl have to say to confirm it but i tell u what ive pretty much done everything else including hoses over the past year and a half and thats about the only thing i havent done yet.

**stockyvrcalais** · 22-05-2010, 05:59 PM

yeh no worries, that idler pulley is pretty much directly under the alternator you cant miss it, also you might wanna try ringing some auto parts places like supercheap, repco etc etc for water pump prices, you might be suprised they can be pretty cheap too sometimes, goodluck mate.

**dope505069** · 22-05-2010, 06:05 PM

Yeah they can be cheaper I know what u mean Thanks for you help mate much appreciated if i fix it or change the pump ill let u know.

**dope505069** · 22-05-2010, 06:08 PM

Ne1 else got any input for this one 13 views and only one helper?

**jay_wr8** · 22-05-2010, 06:21 PM

I'm gunna say water pump to

**Sabbath'** · 22-05-2010, 07:32 PM

Just change the pump. Chances are the impeller's stuffed. Dont forget to loosen the bolts on the waterpump pulley before you take the belt off.

**dope505069** · 22-05-2010, 10:12 PM

Ok thanks guys

**dope505069** · 23-05-2010, 02:11 AM

So what if its not the water pump as you all believe what would be the next option?

**dope505069** · 23-05-2010, 08:28 PM

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**dope505069** · 24-05-2010, 02:43 AM

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**vt josh** · 24-05-2010, 06:10 AM

change the water pump

**vt josh** · 24-05-2010, 06:13 AM

well if its not leaking and your not losing and cooland it cant be much more else when you change the pump take photos and maybe we can tell you what went wrong

**vxcalais_01** · 24-05-2010, 06:30 AM

could be air in the system. DO you bleed it through the valve on top of the thermo housing ?

**stockyvrcalais** · 24-05-2010, 08:59 PM

i know on the pre ecotech (buick) v6, the bleeder is on the thermostat housing, not sure of the eco though

**dope505069** · 25-05-2010, 01:19 PM

yeah I have blead it thanks for your other suggestions guys I think this weekend I guess I will be changing the water pump I will take photos and chuck them on thanks again for all your advice it doesn't go unappreciated.