'98 S70 T5 on it's death bed...coolant issues...

[babygirl2866]

I'm having a similar issue...I have a '98 S70 T5, drove great until one day it blew the heater core..That's where the mess began. Replaced it then three weeks later it blew it up again!! At this point I didn't want to spend more money on another one, assuming there had to be another underlying issue, so I temporarily bypassed it. Ran fine (with no heat of course) until one day it started spewing coolant out of the reservoir. The temp gauge never moved above the three o'clock position, and it usually runs between the four and five positions, which it would intermittently after the coolant loss issue started. With no other choice of another way to work, I kept driving it and refilling the reservoir with water every morning, and driving it roughly 75-100 miles each day for about two weeks. I also have '97 850 GLT (all stock minus the turbo which is out of an '05 S60 I believe) which is my parts car which I used the reservoir out of to replace the one in the S70 as well as the cap to no avail. I have checked for leaks (in hoses and found none, however there was a small crack right at the top of the radiator below one of the lines on the passenger side-I'm currently in process of swapping it out with the parts car radiator), never found any visible signs of the coolant leak, no puddle under the car nothing wet under the hood, etc., done a combustion gas test (which was a burning disaster!! learned the coolant system is pressurized, and up until it hit normal running temp when it shot boiling coolant out the reservoir, into my tester-filling it with coolant and ruining my test dye and all up my arm, the test was negative for combustion gases), compression test (wet and dry on cold and warm engine with moderately normal results), and thermostat/ECT swap from the parts car (though the temp read normal the whole time...? unless the ECT would cause a false reading if it were bad..?).

Im completely stumped and I'm leaning, very reluctantly, towards a bad head gasket.. I'm pretty sure the valve stem seals have been bad since prior to my owning the car, as it smokes in the morning at startup, and it isn't really distinguishable whether it's white or blue in color, very close to both. Yet once its warmed up the smoke is gone. At the end of the two weeks of driving it with the mysterious coolant leak, what led to my having it towed home out of fear was suddenly the oil light came on, I pulled over and checked it with none on the dipstick, added two quarts that I had in my trunk, drove three miles to a gas station, added three more to get it to read where it was supposed to on the dipstick as well as adding half a gallon of water, and continued down the road on my way home. A few more miles and smoke starts pouring profusely out from under the hood(right about where the coolant reservoir is), as well as out the exhaust and some even came thru the vents into the cabin. The oil light came back on as well as the coolant light and right as I was now pulling into a McDonald's parking lot to throw in the towel and call AAA it started making a horrible knocking-like noise from the engine..At that point, I popped the hood to see if it was on fire and attempt to pinpoint the smoke's origin to find the PCV hose on top of the valve cover had blown off and the entire engine compartment was soaked in oil. The coolant in the reservoir was boiling out from under the cap(again...) and I officially gave up and lost all hope for the last time.

Now I'm trying to decide whether to put the 850 engine in it, or the engine from my other '98 S70 (identical cars, minus a few upgrades on the dasly parked possible boat anchor in my driveway), as I would love to keep the outer shell of it and use this opportunity to drop a manual tranny into it (which I have yet to find one in good condition...).

ANY and ALL help would be MUCH appreciated, because I'm almost to the point of having my local junk car pick up service come out and take all three of them, even though one runs and drives fine...

Thanks to everyone in advance!

[tryingbe]

Do compression test on both engine and see which is better.
You can use a turbo 850 turbo engine in a 98 S70 turbo just fine. Use the fuel system on the S70.

I'd change all the seals before putting the engine in, if no record for timing belt/waterpump, I put those in as well.

Putting a manual transmission is would cost somewhere in the $500-$1000 mark. Flywheel, clutch, pressure plate, throw-out bearing, master cylinder, slave cylinder, 3 qt of oil, clutch hoses, clutch pedals, shifter, boot, shifter cables, clips, and etc, they all can add up very quickly.

Here's what I had to do to get a worn out car working again.
https://www.matthewsvolvosite.com/forums ... =1&t=76509

[rguzz]

Sounds like way too much work to me, unless a beautiful specimen maybe this thing should stay dead. Unless you need another parts car I'd get rid of it and start over looking for a vehicle that's in good shape overall. You'll be working on this car for weeks then spending a few months after that worrying and sorting out things that might be next in line for repair as you drive it to and from work. Miles on this car? Too much anxiety for me, but you may be of stronger constitution, and I don't do as much as many of you seem willing to do. Not to mention the cost in time and $$$. Does it need other repairs or do you think an engine replacement will keep you good for a while? I'd look for a good clean one, vetted well, for a couple of grand and start over. That would be me, though. You could get lucky, replace the motor and be good...you never know. Or you could have everything else fall apart after an engine transplant. If I sound somewhat old and tired it's because I am. Good luck either way.

[E Showell]

Forecasts of a viking funeral may be a bit premature -- I had the same coolant-boiling-out-of-the-reservoir issue with a '98 V70 non-turbo. I changed the ECT, thermostat and coolant reservoir cap and had zero issues thereafter.

With a reservoir cap leak, the coolant will boil out of the reservoir leaving no trace of any kind of leak except perhaps a little dried residue on the reservoir screw threads for the cap. It will drive you nuts looking for a "leak," but you'll never find one.

Also, check all of the various coolant hose clamps.

[beigg]

Re-check the radiator. From what I am reading, the internal oil cooler of the radiator might have breached its joining point that separates the coolant and oil. If that internal barrier is no longer keeping the fluids from exchanging sides, it will cause all what you are experiencing as a probable result. As a possible quick check to see if it's the issue, pull the upper radiator hose completely off and observe for a milkshake/smoothie like substance. Could even appear frothy or resemble loose curd goop.

Hopefully it's not too late and you can save the brick!