Overheating v70xc turbo awd

ODONOVJ · Post by **ODONOVJ** » 29 Jul 2013, 15:33

I have been trying to diagnose what I thought to b a failed head gasket. I thought that I would just scrap the car and get another ,easier said than done after putting years of work into it. Anyway I decided to try one of those additives to seal the try and repair it.I didn't have much hope in it ,but ,heh, why not try.
So now the milky foam is gone from the oil and which leads m to think that , maybe the head gasket is sealed.I filled up the reservoir and have on about 10 occasions let the motor run varying between 15mins sometimes and as long as an hour on my most recent . The coolant level stays steady and the temp stays at 3 o'clock. BUT when I drive around the block for 5 minutes , it overheats and the level in the reservoir goes right down.
So, my thought is , Is the head gasket sealed? and why is it over heating when I drive even though it does not overheat when sitting in park for a solid hour?
All thoughts will be greatly appreciated . Thanks

Post by **abscate** » 29 Jul 2013, 18:56

At idle your car is burning about 300-400 mL of gasoline per hour, sitting still.

Thats heat load X

Driving around town, you are burning about 4-5 times that amount of fuel

Thats heat load 5X.

Your coolant is exceeding the atmospheric boiling point and requires pressure to stop from boiling - about one atmosphere or so. I suspect the damage to your block or head is leaking the pressure - ergo boiling coolant.

Post by **Ozark Lee** » 29 Jul 2013, 19:09

Rent a block tester from Auto Zone.

You need to buy the fluid which is $7.00 or $8.00, somewhere in that general vicinity. The block tester sniffs the coolant for exhaust gases and the fluid changes color in the presence of exhaust. It isn't 100% accurate but it is very close and it is certainly cheap and easy.

If the block tester says it is bad then it is bad but if the leak is very slight the tester may not detect it. As such, the block tester saying it is good doesn't necessarily mean with 100% certainty that it is in fact good.

...Lee

ODONOVJ · Post by **ODONOVJ** » 29 Jul 2013, 20:17

Thanks for the replies guys , I'll be sure to try the block tester. BTW is it a straightforward procedure?

ODONOVJ · Post by **ODONOVJ** » 29 Jul 2013, 20:26

I googled the block tester , I suppose the tester is to be inserted into the coolant reservoir of the v70 given that there is no radiator cap,. Right?
Then again wouldn't a compression test be the way to go for that. Anyhow ,what else would cause my condition if it is not a failed head gasket, that's pretty much what I'm trying to figure out.eg thermostat , relay , fuse, timing , etc etc , I'm just throwing random thoughts out there .Could it be something so small I'm just not seeing it. And no there is no obvious drip from any hose or reservoir cap..

Post by **Ozark Lee** » 29 Jul 2013, 21:31

The block tester is indeed used at the overflow tank.

They don't explain things real well in its instructions and if you just keep squeezing the ball it will ultimately draw a vacuum and not suck in any more air. I cock the rubber stopper just a little bit to allow a small amount of air in so that it can keep sniffing for fumes. You will have plenty of fluid so, just for fun, try sniffing your tail pipe with the tester and see the color change in the fluid. The change won't be as quick at the overflow tank but if there is a head gasket breach it will get to that color eventually.

...Lee

ManManOhMan · Post by **ManManOhMan** » 29 Jul 2013, 21:35

Have you inspected other possible causes for the car to overheat(water-pump, fan, radiator, or leaking heater core)?

Will a blown head gasket always make a car over heat?

mfagus · Post by **mfagus** » 29 Jul 2013, 21:42

ManManohMan, every car i have ever seen with a blown HG overheats.

Mark

Post by **abscate** » 30 Jul 2013, 05:24

ManManOhMan wrote:Have you inspected other possible causes for the car to overheat(water-pump, fan, radiator, or leaking heater core)?

Will a blown head gasket always make a car over heat?

The coolant needs both the chemical and pressure to keep it from boiling at the design heat load from the engine. If you were to release the cap at idle after a hot run (DO NOT DO THIS) the coolant will immediately boil and spurt out...burning you badly in the process, due to the release of pressure.

Head gasket leak means no pressure means overheat.

ODONOVJ · Post by **ODONOVJ** » 30 Jul 2013, 08:11

Good point.