VP 93 issues, HELP!

[bunga]

i have a problem and im not too sure what is wrong with it and i cant be ####ed paying to have a mechanic look at it if it is an easy fix so heres the details

the car over heats within 10 minutes of being turned on and water spits out of the exhaust.
there isnt a leak with water as i dont need to refill it at all.
somebody i know said it may be a crack in the head or a blown gasket but as i said i would rather find out on here and see if there is anything i can do to fix it without going to a mechanic

any help is greatly appreciated!!

[jmpez666]

sorry mate but sounds like a head gasket. check for milky brown residue under radiator cap and oil cap

[chevyshubox]

First thing I thought was head gasket as well or maybe a crack in a head as a worse scenario.

[mr.vandervloet]

if its not milky under the cap etc, is your thermo fan working/blocked radiator/thermostat?? usually water coming out is condensation as well.. i noticed a friends commodore had the same issues and had radiator replaced,thermo replaced even though the fan worked as it was overheating bad..

[Jxw]

Are you running anti corrosion inhibitor or straight water? when was the inhibitor last changed? what color is the coolant, green, rusty etc? Is there a massive buildup of rusty crap on the rad cap when you took it off? How does the engine run, smooth (well as smooth as a these engine can be) or does it miss and cough?

i'd check the thermostat and make sure it's not seized, easy enough to undo the 2 1/2" bolts on the housing and throw it in a pot fully submersed under water on the stove and boil it (if it opens when the water is boiling it's ok, grab your nearest wetbix packet, cut a new gasket and put it back in, if it remained closed or just partly open and didn't move replace it)

How old is the water pump? does or has it recently made any nasty noises?

Is the thermo fan kicking in? if so when the gauge is at about 1/4 or just above? If the fan isn't coming on at all i'd replace the ecu temp sensor.
this really shouldn't be causing it if the car is overheating within 10 mins of being started, that points more to a blockage/lack of flow of the coolant.

Pressure test the cooling system, if it holds pressure and the gauge doesn't drop then you may be ok and it's possibly a stuck thermostat/blocked radiator etc.
You can try reverse flushing the radiator with a garden hose, if may dislodge some blockages but ideally you're better off using the proper attachment that fills the radiator with water via a hose and then blasts compressed air through (if you're inventive and good with your hands you can make something up to do this).

Compression test all the cylinders, if they're all much the same you're good, no probs with heads or head gaskets, if you find 2 cylinders low on compression next to each other then it's possibly a head gasket, 1 cylinder lacking compression then maybe a cracked head or gasket.

If the pressure is dropping on a pressure test first place i'd look is the intake manifold gaskets and/or intake for corrosion allowing water to get into the intake ports under pressure when the engine is running (when this happens you don't always see the signs of water and oil mixing in the sump/radiator as the water goes straight through the combustion process and out the exhaust) easier, cheaper and quicker to pull the intake manifold off and check this/replace them than pulling the heads off.
The cast iron heads are pretty resilient, fairly difficult to warp/crack one.

Now being the lazy person that i am i have a similar problem with one of my cars, it uses water but very very slowly, no signs of external leaks, no tell tale signs with the oil or water mixing.
As the engine is due to be pulled out at some stage and given an overhaul/be replaced i just keep driving it, it has overheated once (gauge went past H and the dash started beeping at me etc) when i first found out the water was going somewhere (just before this i had replaced the water pump as it had a small leak), now i just keep refilling it every 2 - 3 weeks when i hear the gurgling/bubbling noise from the dash when i turn a corner and accelerate. It's been like this for over a year without getting worse (touch wood) and the leak has been located to the intake manifold gaskets, pressure tested the system and it failed, compression tested the engine and there was so significant decrease of compression over all cylinders, so the heads and gaskets are still fine.

If you have the milky brownish residue on your oil filler cap then it maybe something more drastic like a head gasket, i'd be doing the above things before going any further pulling heads off and replacing head gaskets.

[VPRob]

Hey, Jxw, good response above. I agree that it is worth checking for cooling system probs before writing off that motor. It takes a fair while to get a 3.8 litre V6 up to temp and it may well just be spitting condensation.
Also I'd throw a can of bars leaks into your cooling system as it might save having to refill the coolant every few weeks. I have no affiliations with said company but have found it to be an effective product when inlet manifold gaskets are suspect...... I bet this suggestion provokes a tirade of abuse. Worth noting that addition of bars leaks will make fresh green coolant look brown and oily and decidedy suss but it is the finely ground leather and the oils in the product that causes this
cheers

[Jxw]

In the current temperature i've noticed it'll take a 3.8 about 15-20 mins to get to full temp and turn the fans on from a cold start letting a car idle, recently had he joys of trouble shooting faulty ecu temp sensors on a couple of them.

Yeah i've read/heard good reports on bars leak and similar products, even the factory gm pellets (forget who the company is that makes them and they sell an off the shelf version to) heard they also contain ground up nut shells and the like which works by filling in a small hole and expanding? as a band aid repair, damn ethyl glycol and its water tension changing properties... put that in and you start finding leaks you didn't know ya had when it pressure tested and held straight water fine lol.

Regarding pressure testing, you could theoratically take it to radiator specialist/mechanic and pretend you want a quote for the repair as long as they do those for free and you don't feel to bad doing it if you can't get access to the equipment easily.

[VPRob]

yep, I agree. Maybe bunga will let us know how he gets on

[Jxw]

so how'd ya go with troubleshooting? we're dealing with a design that hasn't changed much in 100 years, efi or carby it still needs the basics to run right, hope you got it sorted out and running.