VR Overheating

[Skater_jj]

Hey Guys, I have A VR commodore 3.8L and I'm having overheating issues, when my car idles and I have my radiator cap off I'm getting alot of air bubbles in the water, I've been told it was due to a blown head gasket but I've checked both head gaskets and both are fine, i even replaced them with high performance ones, I also snapped the metal end off the heater valve tap inside the heater hose which i have just recently replaced with a brand new one which i know would have no effect or cause to the car overheating.

I have twin thermo's one mounted to the radiator on the motor side and one mounted on the opposite side near my front bumper blowing air into the radiator itself and the car still overheats, my water pump is brand new so I doubt that may be the issue unless it's a dodgy ass one and dont work.

I know my thermastat is correct due to the radiator getting extremely hot and sometimes the overflow tank gets blasted by alot of hot water and steam and the O/F tanks lid blows off.

I've tried looking at alot of possible issues but haven't seemed to find a solution and hoping some of you guys may be able to help with the issue

[jimbojones889]

try a system flush, change the thermo and check for blocks in pipes or even just change them. i had mine overheat when i bought it and racv found it was just the thermo. and the flush really helps too. see how u go

[JA2Z]

Yeah definately try flushing,

When you're doing it make sure you flow a lot of water through the radiator Backwards (in at the bottom pipe is backwards), a forwards flush is good because you can put water at a higher pressure through the radiator, but a reverse flush will actually dislodge any debris causing blockages.

Also when you're refilling you must use coolant, engines are actually Not designed for water (particularly chlorinated tap water), water in engine cooling systems causes rusting and hence blockages, coolant concentrate fluids you mix with water (destilled preferably, 4L for $5 from a supermarket) to provide a corrision inhibiting liquid that transfers heat much better than straight water that will help with your overheating. (however tou can certainly use water if there is no substitute.)

hope that helps

cheers

[Skater_jj]

i've never done a flush of the radiator before but i know the old owner used that seal a crack stuff in it, just curious should i flush it a couple of times til the water comes out clean and not a dusty brown with chunks of that seal stuff in it, and should i run the car while flushing it and if so for how long during each flush, also how do you reverse flush the radiator lol :S sorry kinda new at this i usually only work on motors not radiators lol

[Skater_jj]

anyone able to give me some info on my above post

[vs5lute]

Did you bleed the air out of the system when you refilled with coolant?

[Skater_jj]

i haven't done the flush yet as i have no info on how to do it properly without having to take it to a proffesional to do it, so trying to get the best advice i can on how to do it before i even attempt to do it

I've tried calling the place here who does it in the town im in, and they refuse to give any info out to me, saying that it's bad for thier business and 1 less customer they will have, like i said to them if i can do it myself then i will as they charge nearly $400 for a single straight flush and i know they aren't the best people to go through as the last radiator my old workplace sent a radiator in to get flush, 3 days after we put it back into the VS we were working on, the radiator blew up due to being blocked >.>

[dollyysb69]

Hey mate its dolly and you guessed it one who loves cars, I have been having the same problem as you with the overheating, funning my mechanics also my brothers best mate so when he put a new waterpump in for me b4 xmas you think he would of changed the thermo but didnt. Ever since then my over flow continually needs to be filled with water before I go out. I'm at the stage now where I feel like walking in to the local and dragging him out so his sober enough to fix the problem. Top bloke we doesnt like the piss him a little to much.

I red about the backwards flushing and am going to give that ago, funny before i took my car to this other bloke that used to work with my mate a holden hornsby i never had a prob with over heating. When I got it back after some work done for rego the air con didnt work, it had worked fine before new bushes radiator cap tyres etc wouldn't think any of this would have affected the temp. 3 weeks later my gearbox went got a recon with 12 mths warrant so far so good. However the car continues to loose water from the over flow till its dry and you can squeeze the hoses together when the cars hot and running, is this the norm? Did you find out weather the car need to be running when you flush? Any help would be appreciated from anyone

[patskies]

Id change the thermostat too while your at it. you will be taking it out to reverse flush the system anyway....

[m1chael1o1]

i would change engine water, prob solve ur problem