Need Help finding Coolant Leak!

gordo850turbo · Post by **gordo850turbo** » 11 Oct 2016, 21:46

I have a '95 850 Turbo that is leaking around the rear of the water pump. The leak came suddenly and was severe. After driving about an hour, I parked it for a couple of hours and came out to find a puddle under and around the passenger side tire. The water pump had only 23,000 miles on it. It was a Hepu pump. So I replaced the pump with a Aisin and it still was leaking (under no pressure). Thought that maybe the timing belt guard was interfering with the pump seal so we took off pump and reinstalled again with a new gasket making sure to keep the guard away. Still leaking under no pressure. The water is coming from the top of the pump area. We checked the coolant line coming out of the head. Can't see any leak, but it is wet underneath it. Thought that maybe the leak is coming from the other side of the head from the thermostat housing and running across the bottom of the head. The car is up on ramps so it is down hill to the back of the head. Can't see much under thermo housing unless I remove the power steering pump. My question is whether it is common for the head coolant line to leak under no pressure? Or the thermostat housing to leak under no pressure? Or to redo the water pump again? Unfortunately I can't risk driving it until I find this leak!

Post by **tryingbe** » 11 Oct 2016, 22:42

Did you check the coolant tank and make sure it is not cracked?

gordo850turbo · Post by **gordo850turbo** » 12 Oct 2016, 06:28

Yes. All hoses above the water pump are new and dry.

Post by **abscate** » 12 Oct 2016, 10:52

Its possible the engine block is cracked around the water pump, which jackets the coolant to the engine

It is making me ill typing that.

Post by **sleddriver** » 12 Oct 2016, 12:47

https://www.matthewsvolvosite.com/forums ... 05#p414605

Post by **scot850** » 12 Oct 2016, 15:37

Check if you can get some dye to add to the coolant and a black light to shine on it so see if that can help direct you to where the source is. It may be something you can rent.

When you replaced the gasket did you scrape the old gasket off to clean it? You may have to remove again and check that there is not a gouge in the surrounding face where the gasket sits. It may not have been you but the PO to you and that was why he passed it on!

Did you use and gasket cement when fitting the new gasket?

Neil.

gordo850turbo · Post by **gordo850turbo** » 12 Oct 2016, 20:28

I put pressure to the cooling system. Water was dripping from the middle of the top of the timing belt cover about at the head base. I thought that it could be one of the two freeze plugs behind the cover in the end of the head. The only reason I knew they were there is because I happen to have another engine that crapped a timing belt on a engine stand. I took the timing belt cover off of that one to see what could be leaking behind. So on the engine I'm working on, I broke out a hole in the cover where the upper freeze plug was and took a look. Looked like new and nothing leaking there so I didn't go on the the second one. I put more pressure to the system and the water ran out and it started leaking air. It now sounds like the area of the coolant pipe going to the head by the exhaust manifold. I can definitely hear air coming out in that area. Hard to see anything. I was able to tighten those two bolts a little when I first found the leak. Can them being a little loose cause the gasket to go bad to the extent of the water just running out? Anyhow, I'm ordering a new gasket and will try to put it on. Not looking forward to it!

Post by **scot850** » 13 Oct 2016, 13:06

What always helps us if you are able to, is to upload pictures of the area(s) you are concerned about as it can help us orientate what you are telling us.

I wish you luck if it is the pipe I think you are talking about!

Neil.

Post by **pvfjr** » 14 Oct 2016, 10:58

gordo850turbo wrote:I put pressure to the cooling system. Water was dripping from the middle of the top of the timing belt cover about at the head base. I thought that it could be one of the two freeze plugs behind the cover in the end of the head. The only reason I knew they were there is because I happen to have another engine that crapped a timing belt on a engine stand. I took the timing belt cover off of that one to see what could be leaking behind. So on the engine I'm working on, I broke out a hole in the cover where the upper freeze plug was and took a look. Looked like new and nothing leaking there so I didn't go on the the second one. I put more pressure to the system and the water ran out and it started leaking air. It now sounds like the area of the coolant pipe going to the head by the exhaust manifold. I can definitely hear air coming out in that area. Hard to see anything. I was able to tighten those two bolts a little when I first found the leak. Can them being a little loose cause the gasket to go bad to the extent of the water just running out? Anyhow, I'm ordering a new gasket and will try to put it on. Not looking forward to it!

I just replaced that gasket myself, it's certainly a tight spot. One thing that will help you is to put electrical tape over the bolt head, then stick it into your socket. The electrical tape will take up the clearance between the bolt and socket, so that it stays in the socket better. This will allow you to use a socket extension to get the bolts threaded. Having a small dental mirror, small magnetic light, and/or endoscope can really help.

gordo850turbo · Post by **gordo850turbo** » 15 Oct 2016, 09:43

So it is possible to do! That's encouraging. I will try your trick. My wife's a hygienist, I'll get a mirror from her.