boilover

cet · Post by **cet** » 19 Jul 2012, 23:46

Need help with the aftermath of an experiment of the "indestructability" of the in-line 5.

Cooling system had been trouble free for the 3 years since installing a junk yard radiator (cracked tank).
a few months back did a heater hose bypass of the heater core after it had been decorating the windows.
at about the same time noticed a small radiator tank leak, put in some Bars leak, leak stopped.
last few weeks have been feeding system a liter/week, also noticed the coolant resevoir to be puffed up as if it have been overpressured. observed temps have stayed normal, even when the red "coolant low" light6 came on. had not added much this week just bled some steam off the bottle and the fluid expanded enough to extinguish the light.
tonight the system blew off a liter while parked, i thought it had breached either the bottle or the half inch feed hose underneath so i grabbed a peice of newspaoper and loosened the cap= Vesuvious.took twenty minutes to cool enough and take enough water to feel it in the upper rad hose.drove anouther 5 mi with the cap on "loosley" car started makeing a sound like "octane knock" shut it down immediatly. took thirty min to install 1.5 gallons of water but left car behind for an overnight cool down. Will try to drive it the 5 mi home tomorrow.

will the water pump stop circulating water even if spun by cam belt? Should i replace cap and bottle or just cap. will definatly flush and instill proper coolent mix. The car has always stayed normal if pressurised, thanks for your help.

Post by **erikv11** » 20 Jul 2012, 08:33

The first half of your post really sounds like there may be a head gasket leak, so that combustion gases are leaking into the cooling system and overpressurizing it. First thing I would do is check the coolant for combustion gases, there is an easy DIY kit for it or you can have the shop do it.

No need to replace the bottle unless it is leaking, or visibly cracked or damaged, I'd only replace the cap, if you decide those parts may need changing.

Water pump should keep moving coolant as long as it is spinning, unless the impeller blades are broken off or something internal like that - I think you would know, it would be super noisy.

TERINASSsydwayz · Post by **TERINASSsydwayz** » 20 Jul 2012, 11:22

I had a pesky leak on the wife's car that did maybe .5-1.0L/wk and it turned out to be the nipple on the bottom was cracked very slightly at it's base and when the system got hot enough it would vent out of this crack, after a 1k vacation the last 10 miles before home steam started comeing from the passenger side hood seam and i turned it off and was able to coast about 1 mile into a god sent abandoned lot with a water spicket. I finally figured this thing out and welded about 10 small zip ties over and around the crack with a lighter and it got us home. JY part was on it the next day.

cet · Post by **cet** » 24 Jul 2012, 10:41

Thank You for the help. Got car back home safely. On inspection, it looked, at first, that the hose was leaking at the nipple/bottle joint, but it was a crack in the joint itself.Had one application of plasticweld epoxy last 4 hrs then blow out. removed unbonded epoxy with knife. running now on second epoxy application, we shall see.

I can see the possibility of head gasket, but i see no oil contamination, no white smoke and the engine is running better than ever. (remarked to myself "what a fun car this is" just before the blowout). It did occurr just after 500 ft hill climb, but with mostly anti freeze in and all the crud washed out it is cooling like a Volvo; one needle width up from normal when you climb a hill, one needle width down, when you are running 2200rpm going 60. So there would probibly be pressure transients to go with the thermal.

My problem still is keeping recommended pressure on the system. My go to used foreign parts supplier is out of bottles, which is a good indication that 850's have an appetite for these (like heater blowers). I had My 1984 Renault Alliance scrapped out, or I would have, at least, a temporary replacement. there where a lot of European cars that used these Bosch bottles. Is there anyone around Pittsburgh with a used bottle? If it can hold pressure and a european style cap i will rig it in there somewhere.

on line sources have new bottles from $10.25 to $80, but still need a bridge over delivery time.

Thank You for your suggestions, will report back.

Post by **erikv11** » 24 Jul 2012, 12:05

Hopefully replacing the tank will fix it. I would definitely keep working on that.

The reason I say consider the head gasket is because it is an odd occurrence that within a few months three different places gave out - radiator, heater core, now reservoir tank.

For the record a head gasket leak does not have to involve poor performance, white smoke or oil in the coolant. Those are common symptoms but it all depends on where the leak is. The head gasket separates three compartments: combustion (cylinders), cooling (coolant) and lubrication (oil). You can have a leak than involves any 2 or all three of the chambers, and the leak can go in both directions (back and forth) or just in one direction. On this engine, combustion gases into the cooling system a is pretty common one.

Post by **rspi** » 24 Jul 2012, 15:40

Head Gasket Replacement

Just got finished doing a head gasket job on our turbo S70 GLT. The car had the strangest head gasket leak, one that was new to me. You can skip the story if you'd like.

A few months ago my daughter (from college) called and said that she was having coolant problems. When she started the car, the low coolant light would be on. Then she would drive and the light would go out within minutes. After about a week, she call and told me what was going on and I told her to check the reservior while the car was cold, and if it was low, add some while it was cold. So she went and picked up some coolant and needed to add some. This went on for weeks, weeks turned into months. About 5 months into this cycle she came home for the summer. Right off I didn't have a chance to check it out and a few weeks later she went on a road trip 550 miles away (same weekend I was taking one 750 miles away). So, I told her to check the level before she left and top it off, and stop every 200 miles and let it cool down and top it off. Off we went and no, she didn't top it off. 4-1/2 hours into our trip she calls me and tells me that she has stopped on the side of the road because the car started to overheat. I had always told her, if you ever see that needle going into the red, stop immediately and turn the car off. If you don't, it will overheat and destroy the motor. So, it was out of coolant and the overfill line from the res to the thermostat was split. So she added bottled water and drove to the nearest AutoZone at 45 mph. Hose replaced, coolant filled, and off she went, no more problems at all (other than the coolant getting low every few hundred miles). I believe God had mercy on us and maybe using full synthetic oil helped as well. She got back home fine and a few days later I test drove the car. Before starting cold it was at the min mark. After driving 6 miles it was at the full mark. After driving another 3 miles it was above the full mark and the res looked stressed. After another 5 miles coolant was escaping from the res cap. That's not right. So after speaking to several mechanics I came to the conslusion that there was a small breach in the head gasket. Combustion / exhaust air was getting by the head gasket, into the coolant system and forcing the coolant into the reservior and out the cap, leaving the block without coolant (if none was added regularly). There was no oil in the coolant, no coolant in the oil. My guess it that many head gasket leaks start this way and people keep driving until the block is dry and it cracks or totally blows the gasket (fluid mixing, smoke, etc.). So, I decided to replace the head gasket before she missed a refill again and destroy the motor.

Post by **erikv11** » 24 Jul 2012, 16:17

This story describes exactly the kind of head gasket leak I am talking about.

It is actually one of the most common types you will see on many modern engines where the walls in the head and block can be very thin: a one-way leak of combustion gases from a cylinder into the coolant passages in the head/block.

And when it happens, weak spots go first, to compensate for the overpressurizing. Radiator core, a weak spot in the rad, an old plastic coolant tank, a weak hose, etc.

The test is simple and unambiguous, most auto parts stores sell a kit for testing the cooling system for combustion gases.

cet · Post by **cet** » 25 Jul 2012, 22:21

Not discounting the head gasket theory, and some of those symptoms sound familiar.have yet to find the combustion gas test for less than forty bucks.

Still am wondering why with two different caps this has never vented trough the cap.

Will continue quest for a replacement bottle and the combustion products test, thank you all.

Anyone have suggestion of other European cars who have a similar set up, because finding a Volvo specific one seems a lost cause around here (Pittsburgh was not a hot market for Volvo)

Post by **rspi** » 26 Jul 2012, 09:15

Sorry to hear you are in the Pittsburgh are, I was born in the area and was emancipated to get out of there.

Besides that, a $40 kit is cheaper than 1 shop hour. And 100 times cheaper than a professional head gasket job. Most de ent. Mmechanics can do the test. None in my area wanted to do the job because it exceeds the value of the car.