I drive a 2000 S70 GLT and have had a hell of a time buttoning up all of the coolant leaks. I have replaced the rad and it's hoses, overflow tank and it's hoses as well. I have also replaced the heater core, PCV system and coolant line to turbo, have not replaced the return line from the turbo.
Driving down the road the other night I noticed a bit of steam rising from the hood, I immediately pulled off and popped the hood to find coolant misting from the rear of the engine, close to the firewall. It was dark so I couldn't pinpoint exactly where it was coming from but I suspect either the heater hoses or coming from under the turbo's heat shield. Could it be the return line from the turbo? Any advice would be greatly appreciated as it is my only means of transportation.

 

Most likely it is one of the connections to the heater core. They have to be seated just right to be leak free. I would take off the turbo heat shield to see if the leak is coming from there.as well. Also you could take the vehicle to a radiator shop and have them pressurize the system to find the leak. No matter what you do, until you find the leak and fix it, keep the overflow tank up to the proper level, and keep an eye on the temperature gauge and most importantly, the low coolant warning light. You do NOT want to overheat one of these engines......don't ask me how I know...

 

I been having to top up my reservoir lately. Leaking on drivers side. Last week I parked it on some ramps thinking it was probably a radiator hose and finally got around today to taking off some parts to have a look at all the hoses and clamps and they all looked perfect. So I started it and let it hit operating temperature and no leaks. Crawled under it and still no leaks, but dry crusty glycol remnants. Shut the car off for 30 minutes and when I came back I had a small puddle, so crawled back under it and the only wet spot is the one boss on the transmission to final drive. The manual transmission nor final drive should have coolant in them. Any thoughts?

Location

Location

Close up of the wet boss

Zoomed out view of the leaking

Location

 

It has to be the heater hoses, right? The hoses are not leaking at the fire wall, but maybe the other ends, which I can not see, but I know they are over this area. Any recommendations on how to replace the heater hoses?

 

Do a search on replacing the heater core and there are a couple threads that include replacing the hoses. The common place for leaks is the clips that hold the heater hoses to the heater core. They have to be fully seated or you will tend to get drips/leaks. Before I went that route I would look hard from the top of the engine down in the vicinity of where it puddles to see if you can get a better feel for where it is leaking. If you do change the heater hoses, I would go ahead and change the heater core as well as the hose clips, since you would already be halfway there, and if the heater core is original it is only a matter of time before it will need to be changed. Not a hard job, just put some garbage bags down on the front carpets to catch any coolant when the core is removed.

 

Where do the other (non-fire wall) ends of the heater hoses go. Do I need to remove strut brace,air box etc and access down the engine, or thru the driver side wheel well or is it accessed under the car. I replaced all the other hoses and do not remember the heater hoses where they tie in.
i actually went ahead and ordered new hoses just so I can eyeball where they are going. Thanks.

 

A good tutorial I used can be found here: Volvo 850, S70, V70, C70 ? How to replace heater core hoses

Hope this helps

 

that was very helpful. I also found an ipd video on replacing the inlet tube. Question now is should I replace the inlet tube… where it mounts to the turbo, the lip of the tube is worn off at the bottom. In this same location the passenger side heater hose where it goes under the turbo is mushy and wet.

 

I think it is a case of if it is not too expensive to replace the parts, I would consider replacing it and the mushy hose. I mean, if you are already in there working so to speak, might as well......otherwise it might be a case of suddenly having to replace a broken part at a not so opportune moment

 

I am waiting for the new air inlet tube to arrive. Decided to try and pressure test the system after changing heater hoses. Any idea on what a good pressure is?
I did detect a leak at the upper radiator hose at the t-stat, but since tightening the clamp no issues or leaks.


Heater hoses replaced.

 

No idea, but I would think no more than 10 psi should uncover any leak....