Still loosing coolant!!!

MilehighV70XC · Post by **MilehighV70XC** » 06 Apr 2013, 16:35

Any trip I take over 50 miles where I am boosting a lot the coolant light comes on. If I don't use boost on the same trip I loose little to no coolant. Driving around town I don't loose coolant. I don't boost much driving around town.

--Compression is 125-115-125-125-125,
--The over flow bottle does have a slight exhaust smell but test show no hydrocarbons in the coolant.
--No coolant in the oil.
--No oil in the coolant
--Slight white smoke out the tailpipe when cold, goes away once warmed up, and does not smoke under boost from what I can tell
--No leaks from the heater hoses or the heater core
--No leaks from radiator hoses
--New Nissen radiator

I am at a loss, is this the beginning of a bad head gasket. This is not really the type of job I want to dive into without be sure this is the problem. All test of a blown head gasket come back negative except loosing coolant.
All help is greatly appreciated

Post by **cardiegoV70** » 06 Apr 2013, 20:55

My 960 had a hairline crack and slowly sucked coolant.

Check your turbo cooling hose. It's only 6 inches long, the last thing to be replaced due to difficulty, and it can bleed off a little coolant under boosts while driving without leaving puddles when you stop.

Five dollar part. An hour to change. Hopefully that gets it, otherwise you've isolated your problem to the head. Maybe boost less (or never) until you figure it out.

Post by **Pauloil** » 07 Apr 2013, 06:19

my reservoir had a hairline crack, and I only saw it once when I parked on a hill. You could pressure check the system. I would dry everything off with a towel, and then go on a hard drive to see if something gets wet. the hose under the res. goes the a metal pipe that can leak. Look at the heater core also. putting in one new part like new rad could have made the core start to leak. Be careful looking under the res. as the sensor has to be removed carefully. did you put new hoses on when you did rad.? if you just did rad., check how the hoses are after a hard drive.

Post by **rspi** » 07 Apr 2013, 06:43

Those compression numbers are crazy low but I think it's your gauge or you did it with the motor cold. I doubt you have a head gasket problem, it would cause the coolant tank to fill and overflow after a few minutes of driving, pushing all of your coolant in that direction.

The strange thing that I did not know about coolant (like water), it dries real fast when it leaks into the hot motor bay while it's hot. You may want to add some dye to the system and get yourself a black light.

MilehighV70XC · Post by **MilehighV70XC** » 07 Apr 2013, 10:18

I had a shop do all the diagnostics. $400 later and still same problem. Coolant system was pressured tested and held pressure with no bleed off.

RSPI-- I did have coolant blow out of the over flow container, which led me to think blown head gasket. I took it to the shop for that reason. They thought head gasket also but found the t-stat stuck closed. Isn't there a small bypass hole in the t-stat to prevent this from happening if it gets stuck closed? Anyway they replaced it and no more blow out.

I thought the numbers where low also but the shop said it was ok. I will check if the motor was warmed up when I call on Monday. I would think it was since they seem to know what they are doing.

Mentioned above was a turbo coolant line-- Is there a way for coolant to be sucked into the the turbo under boost through a seal that only shows up under boost and not while pressure testing.

If the car was warmed up what would cause the compression numbers to be so low and how bad are the low numbers?
Anything else I should ask the shop? I have never taken one of my cars to a shop so this a new experience for me, and my wallet.
Thanks for the help so far

Post by **Pauloil** » 07 Apr 2013, 15:37

Isn't there a small bypass hole in the t-stat to prevent this from happening if it gets stuck closed? should be. if you get a stat without one, drill a hole in it. the metal line I mentioned starts at the end of the rubber hose under the res. if the car runs well, don't worry about the comp. numbers

Post by **erikv11** » 08 Apr 2013, 07:14

Pauloil wrote:Isn't there a small bypass hole in the t-stat to prevent this from happening if it gets stuck closed? should be. if you get a stat without one, drill a hole in it. the metal line I mentioned starts at the end of the rubber hose under the res. if the car runs well, don't worry about the comp. numbers

Just FYI - I used to do this with all of my cars. However on my turbo 850, the car runs too cold in the winter with a hole drilled. The same stat works fine in the NA, but in the turbo the gauge never gets above 5 o'clock in the winter. So i.e. I would not recommend this for an OEM Wahler (Volvo) thermostat on a turbo car.

Post by **rspi** » 08 Apr 2013, 07:50

The compression numbers should be between 156 and 185. Anything below 156 is low and tells one that there is either piston blow by or leaking valves. Being that it's across the board my guess would be a bad gauge. If they are all low, it indicates even engine wear among the pistons, likely due to lack of oil changes over time at one point in the cars life. There is also the chance that they lied about doing a compression test and did not know the correct numbers and just told you something and charged you for the test.
http://atthetipwebs.com/technologyinstr ... n_test.htm

Not sure if a stuck t-stat would cause pressure build up but it sure will cause overheating real quick. If the car has ever overheated it likely caused a head gasket breach. Some people have pulled plugs and seen them steamed from the head gasket leak. Here is our coolant mystery notes, you can review them.
http://atthetipwebs.com/technologyinstr ... gasket.htm

MilehighV70XC · Post by **MilehighV70XC** » 08 Apr 2013, 08:50

Thanks for the links RSPI- I have seen the head gasket post before and could not find it again in search.
I have owned the car since 78k and have changed oil every 4-6k miles depending on driving condition and how the oil looked. T-stat was OEM and had about 50k miles on it.
I have never had any over heating problems. Anytime the coolant light turned on I pulled over to make sure there was coolant in the bottle. The car has always warmed up and got to operating temps just fine and the gauge stays right at 3 o'clock. I did have coolant instantly start filing up the reservoir once the car was started and not even close to being warmed up. That's why the shop changed the t-stat.
A small breach in the head gasket under boost is the only conclusion I can come to.

Post by **abscate** » 08 Apr 2013, 09:00

I think your compression values are low, but indicative of test method rather than a bad engine lower end. Certainly I would repeat this myself before concluding anything.

This might sound crazy but my 99 V70 was leaking coolant from the radiator, catching it all nicely into the tray below the radiator, and evaporating it all without leaving a trace on the driveway. I too, was getting coolant light every other week, wondering where it was going.

Its worth looking for a leak under the radiator by smell, at least.