1998 Volvo S70 - Large Coolant Leak, but Where is it?

[nickelghandi]

Here is where I am now with it:

Running it to OT results in steady drips. Revving it once it is warm results in flowing/gushing of coolant from regions unknown.

Turbo - Checks out fine. No leaks anywhere aside from a tiny oil leak (to be dealt with later when I source a 16t )
Heater core - checks out. The floor is not wet and it would be with how much I am losing.
Rad hoses - The lower one is bulging, but not leaking - I will replace this one now and you'll see why
Heater hoses - These are fine at the firewall, but I am unable to trace them back to their connections on the block/rail due to space. There is water coming out near where (I think) they connect when the engine is warm/ system is under pressure.

I think these heater hoses are what is leaking. Shining a light down into the deepest darkest reaches indicates a leak in that region and the lower rad hose (close by) is dry all the way around. The hose will have to come off to get access so I will just replace it. I am also going to do the expansion tank hose because it has a death bubble. Not going OEM with the lower rad hose (sorry but the price is just ridiculous for a rubber hose), but I plan to go OEM for the heater hoses due to their proximity to the turbo and other very hot components.

To do all of this I will need to drain the coolant so I will go ahead and flush the system a few times to eliminate any residual oil from the previous head gasket leak. Is it fine to use a garden hose to flush these motors and then flush once or twice more with distilled water before putting in 50/50 mix? I do not intend to do a chemical flush because I have heard bad things about them damaging seals and gaskets but correct me if I am wrong. I am splitting my order between IPD and amazon to get the parts quickly. I almost opted for some pretty, blue silicone rad hoses until I discovered my hoses were the original hoses and they have lasted 150k miles.

I will try to get some pictures along the way even though the space is tight. I haven't yet seen a tutorial on this process so hopefully this thread will be able to help someone in the end. I will update with my progress in a few days.

[cn90]

1. Heater Core/Heater hoses: I did the mod, eliminating all the O-rings, yellow clips etc. See link:
viewtopic.php?t=69238


2. Turbo Coolant hoses x 2, see the link I posted above a few threads above.

If you follow these 2 links and do them, you will be happy.

Re: brand names:
1.Heater core: ebay is good enough. Heater hoses Mod: Gates.
2. Turbo Coolant hoses: this job is time-consuming and the consequence is grave (losing coolant, engine overheat, potential head gasket issues), stick to Volvo OEM parts ONLY!

[nickelghandi]

Alright, I know this thread is not getting much attention, but I am going to continue posting for posterity sake. I found the hose that was leaking. It was the upper heater hose where it connects to the block. The clamp had been tightened so tightly that it cut the hose. The shop that did the head gasket may have done that, but there is no way to prove it so I am leaving that be.

I spent the better part of yesterday fighting with misaligned hose clamps and bending my hands and tools into places I did not think I could get to. I removed every coolant hose, checked for leaks, and put back any that were in good shape. I also flushed the whole system with tap water from the garden hose and then ran 5 gallons of distilled water through the system to clean out any additional gunk. The drained coolant and flushed water actually looked very clean so I am thinking the reservoir was to blame. It was still grimy from when oil was in the reservoir. I cleaned the reservoir with some baking soda and then hit it with some dish liquid and a toothbrush to clean out all the gunk. It is as clean as it is going to get. I might replace it soon.

I am now going to replace that heater hose as soon as it gets in and all should be fine. I am also replacing the lower radiator hose because it is swollen and weeping a little bit. The lower heater hose looks pretty new, so I am leaving it in place.

The turbo lines look pretty new so I am leaving those alone as well. I checked the service records and they were replaced about 20k miles ago with OEM ones, otherwise I would have just done them again.

I also had the benefit of angling all of the hose clamps in such a way that I can easily access them in the future.

The only real problem I have had with this repair is that the draincock for the radiator is not functioning. It turns indefinitely and never comes out. It isn't tight, but it won't move out. It is plastic so I am wondering if it was over-tightened previously and now cannot thread its way out. I just drained the system by pinching the radiator hose with the clamp off to let liquid out, and sticking some aquarium air hose in to allow it to drain. I was afraid to use a metal tool on plastic fittings. It was a bit messy, but it got the job done.

I will update this thread one more time when I have completed the repair and then I'll consider it closed unless someone wants to chime in or ask another question about the repair. Thanks for your help and suggestions, everyone.

[j-dawg]

I always just drop the lower radiator hose to empty coolant. I don't want to risk breaking the drain petcock and being unable to fill the car with coolant, so I accept the slight spillage from the radiator.

[nickelghandi]

I think someone already broke the petcock. At least it doesn't leak. Anyway, yesterday I did the fix. Rubber for both the heater hose and the radiator hose, but both with lifetime warranty from O'Reilly's Auto Parts. While I had all the intake and most cooling hoses off, I also replaced some vacuum elbows that looked rough as well as the upper engine torque mount (thanks rspi for the vid on the press-less replacement), and it feels like a totally different vehicle. It is faster from a stop, and there is zero clunking as it moves through the gears. Passing on the road is seamless and it no longer feels like it is gasping for air. I never realized how smooth the power delivery is on these vehicles until today. I guess having a well-sealed vacuum system makes a huge difference. I had a 1999.5 Nissan Pathfinder and it rode for years with multiple vacuum leaks and had no problems with power or anything. I guess it makes more difference on a turbo. All this thing needs is AWD and it would be a beast.

The next item on the list is the hose from the reservoir to the block. I might replace the thermostat too since I found some gunk in there (probably from the oil intrusion). Then new brake rotors and some braided steel lines. Then finally time for some fun projects: window tint, painting my stupid looking white hood and trunk (on my blue S70), new turbo and ECU from a t5, etc., etc. until I am out of money, time, or desire.

Thanks again everyone for the replies and assistance. Do we do introduction threads on this forum? If so, I will post one with some pics of my S70 and a little about myself and experience.

[abscate]

Great news! Yep, vacuum leaks will kill you on these cars.

Just start a new thread with pics ...we are pretty relaxed on threads here