Mystery coolant leak on V70 T5, 1997

Post by **cn90** » 23 Jan 2013, 10:01

Get a flash light and look.
Sorry, but it is very difficult to guess for you.

V70T51997 · Post by **V70T51997** » 23 Jan 2013, 11:03

Yeah I've got an OK headlamp (900 lumens), but there's so much stuff in the way so I can't see. I guess I'll have to do some part removing and do some more inspecting. Will tell the results after I've done that.

skloon · Post by **skloon** » 23 Jan 2013, 14:10

sounds like the heater pipe that is below the cam position sensor- my recent coolant leak was the nut around the oil cooler fitting had vibrated loose, and there is not a lot of space to swing a wrench on that sucker

Post by **E Showell** » 24 Jan 2013, 09:51

Check all of your hose clamps. Especially if any of your hoses are URO brand (to be avoided), the URO hoses get very hard over time and the hose clamp stops supplying sufficient pressure to seal the hose connection and results in a micro leak that can be very hard to detect.

V70T51997 · Post by **V70T51997** » 24 Jan 2013, 13:04

Yeah I managed to get the turbo intake air pipe out of the way today and checked the radiator lower hose clamping. It was a bit loose and I tightened that up. Then I added some pressure to the system and inspected with fingers if I could feel any leaks or bubbles or whatever. Didn't notice any so left the system pressurized. I think all the hoses are genuine (if not original), most likely I should replace them all but as a student you have to do what you can afford... I'll do some more inspecting tomorrow, there was that leak on the passenger side, I can't pinpoint the location of the leak as it's very hard to see to the back of the engine. I'll get some warm water in a spray bottle and hopefully the water will be enough to tell me where rest of the leaks are. Hopefully won't have to disassemble more than I've already disassembled...

By the way, there was a bit mayonnaise on the intake pipe and PTC valve too. The breather hoses + tank -job was done less than a month ago and every part was renewed (not just washed). Still after less than 1000 km of driving after the job there is that mayonnaise bastard again! What's the most likely reason for that?

V70T51997 · Post by **V70T51997** » 25 Jan 2013, 08:00

I've now located few leaks. I drained the coolant and added some pressure to the system. 1st leak was in the engine side of the heater core hoses (the one that comes from heater core pipe and goes in engine side nipple #976040). The clamp was a bit loose and rusty, also some dirt and stuff inside the hose and the coupling unit that goes inside the engine. I cleaned the parts and used a new clamp. Added some pressure and it didn't leak. Used a 1 m long plastic hose as a stethoscope. The second I found on the coolant temperature sensor, either it isn't tightened as it should or then the seal is leaking.

These are the "easy" ones, but I'm quite sure that there's a coolant leak somewhere on the back side of the engine, as it drops coolant near the water pump and directly on to the passenger side drive shaft which then sprays the coolant everywhere... That's my conclusion on how the coolant is literally everywhere... So I think the leak point is the O-ring #976045 (I have a water pipe #9142745, Google finds explosion images). If it's not that I must raise my hands up in the air and forget the whole deal... Does anyone know the size of the O-ring #976045? Would a regular O-ring set have one? Any luck? I've realized that Volvo uses their own sizes on the O-rings mostly so you can't buy "cheapos" and will be forced to use legit ones. Oh and is the water pipe only attached with 1 clamp? I tried to get it loose once but didn't know how to take it out.

My brother did the water pump job as it was even colder outside near new year, and he tells that he guarantees that the water pump gasket doesn't leak. I trust him, as he's a mechanic and has done so many cars in his lifetime... And trucks, motorcycles, you name it...

V70T51997 · Post by **V70T51997** » 25 Jan 2013, 11:38

Heh. Had to remove upper thermostat cover to gain some room to tighten the coolant temp sensor. After putting everything back in place, I added some pressure to the system and now it doesn't leak from the sensor but between lower and upper housing. So am I good to go only with a new thermostat seal?

V70T51997 · Post by **V70T51997** » 27 Jan 2013, 13:03

I've narrowed the possible leak points in this picture:

https://www.dropbox.com/s/b6hljwdypve6v32/marked.jpg

What are those marked ones (particularly the red one)? Is it supposed to be like that, nothing attached to it? There's "smoke" coming around this area (number 1 are the fuel lines) and I've checked the area quite thoroughly using a mirror, taking pictures when the engine is on and so on. But I can't locate the source! Frustrating as hell.

Oh what I could do if I had a car lifter...

e: the thermostat housing is now ok and there should be zero leaks on any clamps now...

whoa · Post by **whoa** » 27 Jan 2013, 16:41

The red one is the drain petcock. The other one I think is an oil line to the turbo.

I'm having a hard to find leak too ('96 850 Turbo wagon). In addition to the heater hoses there is a very hard-to-get-to hose that brings coolant to the turbo. It's #9 in this diagram:

http://www.volvopartswebstore.com/showA ... bly=239973

I think that's what's leaking for me. By removing the turbo air intake pipe I managed to see the hose and tighten the clamp on the forward end (the side of the hose farthest from the turbo), but I can hardly see the other end, and it looks hopeless to get a tool on the clamp. Would love any advice about that.

(Edit: found this helpful thread: https://www.matthewsvolvosite.com/forums ... 2&start=15)

Mark

V70T51997 · Post by **V70T51997** » 29 Jan 2013, 12:23

I've checked that hose when the system was dry and pressurized and mine didn't make any noise around that area. It's quite cheap though so might order one and change it some day...

There is some splash marks on the timing belt cover, and the coolant is dripping somewhere around that area and on to the engine mounting frame and from there all the way along down to the ground. So it's not helping me to identify the exact location of the leak at all.

Also, yesterday I drove from school to home and the coolant level light pops up. Turn engine off, fill the coolant tank to upper level and leave the car have it's rest. Then I went and checked the leak points under the car and checked coolant level and it had dropped down to lower mark just by standing on the parking lot!

It's getting quite expensive to pour the coolant to the ground... And it ain't environmentally good either...

Mystery coolant leak on V70 T5, 1997

Re: Mystery coolant leak on V70 T5, 1997