1996 850R - Coolant leak frustration

txdave13 · Post by **txdave13** » 17 May 2014, 19:26

I was having a coolant leak after I first got my car. It seemed to be coming from the reservoir cap, but I also had coolant dripping off of the radiator. I replaced the radiator and bought a slightly used reservoir and cap. I also installed silicone hoses coming from the tank and the upper radiator hose. The leak from the reservoir persisted.

I read all about how you needed to get a new cap and tank, so I bought both new from the dealership. I installed them today. At first, everything seemed OK, but then I took it for a longer drive. That's when the problem started.

The temp gauge would rise almost to the red, but never got there. By the time I got home, the low coolant light was coming on. I popped the hood and sure enough, it looked like it had leaked through the cap again. This is a new cap and tank I bought yesterday.

Here are some pics.

In this first one, you can see that it looks like it has been spraying out towards the engine primarily.

Yep, the timing belt cover took the brunt of the spray down.

You can still see some coolant, pooled by the cap. This was two hours after I had shut the car off.

So, where could I be going wrong? Is it possible that the system is making too much pressure and forcing coolant past the cap? Thanks.

Post by **scot850** » 17 May 2014, 22:51

Have you had the cooling system pressure checked to make sure the head gasket hasn't failed? It is not an uncommon problem on older Volvos.

I'm also assuming you have checked the car isn't overheating as you don't mention it. If it is running hot, it could be as simple as a stuck thermostat. For the small cost it is worth swapping out to eliminate it.

Last suggestion would be the water pump has failed.

I'd check it in the order listed.

Oh, one other possibility, have you burped the water system? You could just have an air lock.

Neil.

Post by **E Showell** » 18 May 2014, 04:59

Replace thermostat and ECT sensor.

txdave13 · Post by **txdave13** » 18 May 2014, 07:17

Thanks. I'll check those out.

Post by **cn90** » 18 May 2014, 07:18

1+,

Before you regret.

- Thermostat is Wahler.
- ECT is Volvo or SWF brand. However, this item can wait a bit.

Post by **cn90** » 18 May 2014, 07:18

1+,

Before you regret.

- Thermostat is Wahler.
- ECT is Volvo or SWF brand. However, this item can wait a bit.

Post by **whilst** » 18 May 2014, 12:22

Might also check that your cooling fan is coming on.

Baptiste1106 · Post by **Baptiste1106** » 18 May 2014, 14:57

Replace tank & cap. Looks like your tank is cracked. Purchase from fcpeuro.com

txdave13 · Post by **txdave13** » 22 May 2014, 12:21

Thanks for all the advice guys. The saga continues.

Well, I replaced the thermostat yesterday with a Wahler thermostat. The old looked OK, but it didn't have the bleeder valve that Wahler/Volvo thermostats have. I ran it for a solid 20 - 30 minutes at idle with the reservoir cap off, trying to bleed the system. I ran it with the heater on and with the heater off. There was never any need to add coolant and the car never ran outside of regular operating temperature.

I just took the car for a test drive to see if the problem would pop up. I drove modestly up the highway at speed (70ish) for about 10 miles or so. I exited to a parking lot to check the hood. Everything looked great, however the coolant in the reservoir was up above the MAX marking. I'd not had any coolant splashing from the reservoir and the temp sensor looked normal. I turned around and headed home, planning on a few high speed passes, just to make sure.

Entering the highway, I merged with traffic, then floored the accelerator to pass some slower cars. It wasn't long, maybe 10 - 20 seconds. The car started heating up. I got back into the right lane, took it down to 70, and was easy on the gas. It kept heating up. I pulled off, into a gas station and popped the hood. I could see where the coolant had splashed out. The temp gauge was back to normal, but pulling out of the station, I would get a low coolant light for a second or two.

I was about 5 miles from home and took surface streets from there. The drive home was uneventful, the needle did rise a couple of times, but settled back to normal quickly. After I shut off the car, the coolant drained out of the reservoir. There is none showing. Before I left, it was in the middle between MAX and MIN.

I'm aware of how fragile the head gasket is, and I'm not saying that this problem doesn't stem from a bad head gasket. This just doesn't seem like a head gasket symptom.

Before I switched the thermostat, I ran the car at idle to operating temp, to try to bleed the system (I thought I may have a bubble from replacing the radiator/hoses). With the cap open, I could see that the hose from the top of the thermostat housing was spraying coolant to the reservoir. The level kept rising and I had to shut off the car to keep it from overflowing. Once I switched the thermostat, I didn't see this problem.

So, anyone have any ideas or can tell me how a head gasket would lead to these symptoms? I'm so confused. Thanks in advance.

Post by **E Showell** » 22 May 2014, 12:30

If you did not replace the engine coolant temperature sensor, the thermostat replacement alone may be insufficient to solve your problem. I usually replace them as a set. Cheap insurance.

I am almost certain your problem will disappear if you replace the ECT.