V70 GLT losing coolant - into transmission?

macs70GLT · Post by **macs70GLT** » 07 Dec 2016, 09:32

Quick history on the car, my son bought this 98' V70 GLT last summer on my recommendation. We intended for him to drive it from WA state to NM where he goes to college. PO had told us he did the head gasket due to overheat when his wife was driving it. We bought the car without a good thorough check - just a drive & my looking it over (doh!!!)

I have done various things over the summer including swap out of oil cooler lines (my least favorite job on these), ABS module, changed all coolant hoses etc.

Over the last month it has been losing/using coolant. I did identify a small leak at turbo return rubber hose so tightened that clamp. Last night I ran the UV die through the system & found no evidence of leaks.

However - it was leaking transmission fluid a couple months ago (appeared to be coming out at the axle). I'm now wondering if there is a leak inside the radiator, enough to raise the level of tranny fluid.

1. wouldn't I see signs of transmission fluid in the expansion tank?
2. wouldn't a damaged head gasket (burning coolant during combustion) also show signs of oil in expansion tank?
3. what else can I do to check for coolant leaks?

I have not yet pulled spark plugs to check those for signs of coolant.

Thanks guys!

Mike

Post by **misha** » 07 Dec 2016, 09:35

Does the car have automatic transmission?

macs70GLT · Post by **macs70GLT** » 07 Dec 2016, 11:04

Hi Misha

Yes it's the automatic. I'm planning to drain & fill the transmission with Mobil 1 Synthetic ATF, probably will do it twice in next couple weeks. Then I'm driving it from WA state down to New Mexico.

I should also point out I have not driven the car much, it has been parked. Coolant level has dropped about half volume of expansion tank 2 or 3 times since I replaced all the hoses.

Thanks

Mike

Post by **misha** » 07 Dec 2016, 11:20

Ok....next step would be to check transmission oil level on transmission dipstick.If oil isn't contaminated with coolant and if it is at proper level....than it's ok.
However....if radiator chamber for transmission oil is ruptured it would also contaminate coolant.

Check driver's side footwell carpet for coolant traces....could be that heater matrix is leaking....or could be a headgasket.Maybe the seller didn't replace it like he said before he sold the car.

If transmission oil is ok,coolant ok,heater matrix also ok,no other visible signs of coolant leaks at hoses...than the engine is burning coolant because of blown headgasket.

Post by **rspi** » 07 Dec 2016, 20:32

The bad thing about coolant leaks is that when hot, the coolant evaporates real fast. May never leak to the ground.

#1 check heater core. If it has not been replaced recently, it may be a time bomb.

#2 Check water pump. If it is more than 10 years old or is an after market pump, it may be seeping. Mine leaked for about 18 months before it failed.

#3 Radiator. If it's seeping into the transmission, the transmission fluid will look like coffee with cream or chocolate milk. I have head of the rad leaking into the trans and not flowing the other way. I'm actually planning to bypass my rad with an external transmission cooler.

macs70GLT · Post by **macs70GLT** » 08 Dec 2016, 08:44

Thanks Misha & Robert

The heater core shows no signs of leaking directly underneath, and since I ran the UV die through the system there should have been traces of the coolant/die mix remaining - so I'm considering that good.

If the pump is seeping I wouldn't see it, so that may still be a culprit. I need to change out that motor mount anyway so that will give me a good closeup look of the area.

Regarding the trans fluid, I'll check that again. I've never been confident in reading the level accurately since it varies so much with temperature - planning to drain some & replace with Mobil 1 synthetic in the next few days.

One question - is it possible the system just had enough air after changing radiator hoses that it needed to be topped up 2 or 3 times?? My Audi A4 is difficult to fill, have to elevate the expansion tank to get it done properly.

Robert I'll check out your videos tonight, thanks for creating those! A great resource for the shadetree mechanics ...

Mike

#1 check heater core. If it has not been replaced recently, it may be a time bomb.

#2 Check water pump. If it is more than 10 years old or is an after market pump, it may be seeping. Mine leaked for about 18 months before it failed.

#3 Radiator. If it's seeping into the transmission, the transmission fluid will look like coffee with cream or chocolate milk. I have head of the rad leaking into the trans and not flowing the other way. I'm actually planning to bypass my rad with an external transmission cooler.

Post by **jblackburn** » 08 Dec 2016, 08:51

One question - is it possible the system just had enough air after changing radiator hoses that it needed to be topped up 2 or 3 times??

Re-filling ~2 times seems about right from what I recall.

. I've never been confident in reading the level accurately since it varies so much with temperature - planning to drain some & replace with Mobil 1 synthetic in the next few days.

Check with trans fluid warmed up, car idling in park, trans stick level side pointed at the sky.

Post by **scot850** » 08 Dec 2016, 09:36

Agreed with the several tops up required. I reckon my last radiator took 4-5 fills to settle it, but most have been 1-2 to purge the air.

Neil.

Post by **misha** » 08 Dec 2016, 13:03

macs70GLT wrote:...If the pump is seeping I wouldn't see it...

Yes you would.Just by the crankshaft where right lower engine mount is.If water pump is leaking from a weep hole,coolant would drip under the car and you would see that.
You can also remove timing belt cover and check the area that way.You would have a better view and you would see everything.

KurtL · Post by **KurtL** » 08 Dec 2016, 16:13

I have experienced slight coolant leaks from both expansion tanks on my 01 V70 and 08 C30. I have had leaks from the the radiator, heater core and heater core O rings that were all almost impossible to detect.
The tank is an easy do it yourself fix that is easy to replace and rule out.