We bought a 1999 V70XC about 4 weeks ago from a used dealer. We test drove it and my wife loved it so we took it home. About 2 weeks later a little white smoke started coming out of the tailpipe so I took it a local shop (Adams Import Car Specialist in San Diego). I was told that the car had a lot of blowby and recommmended changing the PCV valve.

We ended up doing the PCV valve about 2 weeks afterwards and I told them I had noticed I was losing a bit of coolant and thought it was coming from the thermostat housing. They changed the PCV valve and told me that one of the bolts to the thermostat housing was stripped. About a week ago I took it to my regular mechanic and had him change the thermostat and upper radiator hose.

Today as I was leaving to work the coolant sensor came on, I went to check and the coolant was at minimum in the expansion tank. I checked the dipstick and the oil looked normal. When i checked the oil cap I noticed a light crystalized fluid swirls, and when I looked into the crankcase the oil looked thick and dark brown. I also noticed there was a bit of oil under the plastic part that covers the spark plugs. Coolant is clean, but when I opened the expansion cap there was a bit of steam? that came out. My worst fear is that it's the head gasket.

 

The system is pressurized so you are not suppose to open the expansion tank cap with the car warm/hot.

When the PCV system is changed, you are suppose to install a new oil cap seal. Some people replace the oil cap as well. They get a little weak after time. If the PCV wasn't done correctly, you still may be having a little head pressure. The entire system should be replaced. The oil on top of the motor under the cover is likely coming from the oil cap seal.

If you had a bolt stripped in the thermostat housing, the housing needs to be replaced. Only 3 bolts hold it to the block. Consider that. Usually the bolt head is stripped, not the threads, so verify that.

These cars rarely have head problems even though I did. Try to figure out where you are loosing coolant. Sometimes the bottom of the overflow tank leaks and sometimes the coolant is leaking from the heater core.

Welcome to the forum.

 

I'll double check for leaks. The thing that worries me is the color of the oil when looking into the crankcase. I'll head to autozone and rent a block tester to see if there are any combustion gases in the coolant. If there are, what are some otherr things that it could be besides the head gasket, turbo?

 

The only color I would worry about would be in the drain pan after the oil plug is removed.

I had a bad head gasket with combustion gasses getting into the coolant area. It didn't give low coolant readings while the car was running, it was forcing coolant into the overfill tank. The overfill tank was overflowing while the car was running, pushing all of the coolant out of the motor.

 

I rented the block tester from Autozone today. I started the car and let it run a couple of minutes before putting the tube to suck in air. I did the test a few times with a couple of minutes in between. About 10 minutes when the gauge was at normal operating temperature I finished the last test, all 4 times the liquid remained blue.
The coolant level was in be between the min and max levels. After turning on the car and while it was warming up, the level was rising until it started to overflow. At that time I turned the car off, but I had already lost quite a bit of coolant. After a couple of minutes the overflow tank was almost empty. I put on the cap and could hear a hissing sound. I went to Autozone and got a new oil filter cap and overflow tank cap.
Once the engine cooled off I topped the tank up to almost the max and took it for a drive. I checked about 25 minutes later and the coolant level was about 2 inches above the max marker. I'll check tomorrow to see if I've lost any coolant. I could still see a faint puff of white smoke/steam coming from the tailpipe at random times. Did I do the block test correctly? I took off the overflow cap and turned on the car and tested it at numerous times while the car was warming up.

 

the block tester is pretty simple to use. you put it on turn the car on and squeeze it to get the gases in the block tester. if youve done that and it still passes then it is good. check your heater core (behind the panels in center console below radio). that is a common source of a coolant leak.

 

READ POST 2, YOU ARE NOT SUPPOSE TO HAVE THE CAP OFF WHILE THE CAR IS RUNNING. You might want to visit your owners manual as well.

Also, you have a Volvo not a Chevy. you may want to put the OEM caps back on. The coolant tank cap is very sensitive on these cars.

 

Having the cap off won't hurt anything.

 

Is it normal for the tank to fill up if the cap is off?

I'm ordering an oem cap today, i got the autozone one to check if the old one was bad.

 

If you are talking about it filling up right after or shortly after you shut it off, cap off, yes. The heat in the engine will expand the coolant when there is no pressure on it and it can fill up the tank or even overflow it until the heat in the engine block has a chance to dissipate.

If you unscrew the coolant tank cap and get a bit of steam it's normal. You have to remember that at normal operating temperature the fluid is 180 to over 200 degrees so it steaming a bit isn't a matter of concern. If you start it up cold and pop that cap off and see steam, you have a problem. If you have it running and you see it bubbling then again it's a matter of concern and best tested.

 

+1 With the prince. I'm dealing with a 960 that has a water pump leak. If the motor is cool, I can remove the cap and add coolant, even when it's running. After the motor reaches about 160 degrees, it's not possible, it just overfills. If the system is low and I start to drive the car it will suck all of the coolant out of the expansion tank.

 

Ogarcia_02, Where are you at with it

 

I am in the middle of replacing my head gasket. Here is what you want to do.
1. Go get some coolant dye.
2. dump it into the reservoir.
3. drive the car for a week. refill coolant as required
4. Check for external leaks
5. Pull the plugs and look for the dye around the plugs.
In my case cylinder one was full of dye.
If I had done this at the onset, I would have saved myself months of guessing.
Good luck.
Jim

 

I'm still tracking the leak. Funny thing is that a couple of days ago we want on a longer drive about 70 miles and there was very little coolant loss, about a quarter of an inch. When we drive normally, about 15 miles the next day i have to add about an inch of coolant. I've noticed that the loss is greater when we park downhill. Sometimes I'll see a signs of coolant coming from the thin hose from the reservoir to the radiator, but the leak is not always there.

I actually just got some dye so i will try it out.

On a side note, when driving on the freeway if the rear passenger window is all the way down there is a muffled sound kind of like a helicopter? You can only hear it if that window is thus only one open.

 

muffled sound kind of like a helicopter? You can only hear it if that window is thus only one open.

Yup, I don't know why they do it but I've had that happen before and I've seen a few other posts where people have asked about it.

I hate to say it's "normal" but it is something that you need to live with. Or ... if you find a cure let us know.

Helicopter is good, at first I thought it was the joints in the road except too fast and it was asphalt, no joints !!

 

Update:

So I've been checking with a UV light for signs of a leak. I found a leak on the thin hose from the expansion tank to the radiator. I checked the hose and it looked fine but the clamp was rusted and out of shape so I changed it. It stopped that leak but not it is leaking from the thermostat housing again even though my mechanic changed it already.

Could it be that there is too much pressure in the system and it is making it leak? Every time I open the expansion tank, even after leaving it overnight, it hisses like when you open a soda bottle.

 

If it's "hissing" when you take the cap off cold it's almost certainly a bad head gasket pressurizing the system.

You should have it tested for hydrocarbons.



You can get the kit as a loaner for most auto parts stores. You have to buy the fluid.

 

I did the block test and it didn't change color. However the coolant would overflow after a about five minutes, I would then have to shut the engine and the reservoir would be empty. I don't know if it's related but i also have engine oil leaking from the fill cap even though its a new cap and gasket. I had the pcv system changed and was told that there was still some pressure in the crankcase?

 

The PCV system includes passages in the block and oil pan. Until I saw the whole system I always recommended replacing the PCV black box and hoses like the set they sell at IPD or FCP.

Having seen the PCV black box it's nice to have a new one but unless the lower port is blocked the box is the least of your worries and I think in most cases doesn't need to be replaced. The hoses I would always put in new if they felt brittle or spongy. It's likely they did the box but didn't check or clear out the passage in the engine block and oil pan. It might be why you still have pressure and it's still pumping out oil. Seperate issue from the cooling system.

BUT, for the radiator ... I'd do that test again. IMHO It really sounds like it's a head gasket pumping pressure into the cooling system. Especially if it has pressure even after it's cooled
Overheating is caused by a bad thermostat, cooling fan not working or blown headgasket. Not going to mention a leak as yours surely can't be leaking that much and you don't see it.