Hello. My S70 suddenly is low on coolant. this has never happened before and I am the original owner since '98. Got about 125K miles on it. i noticed this a few weeks ago and added some of my 50/50 Volvo antifreeze/distilled water mix. Now it's low again and I am out of the mix and my local Volvo place has turned into a local Subaru place (darn!) and I do not have a place to grab a gallon of Volvo stuff. My expansion tank is almost empty, the coolant light comes on when I accelerate or turn a certain way, so I am low. The temperature is fine, maybe one bar higher than normal, maybe not (it seems to be in the middle and not close to red zone). It is very cold out today, but I tried to look under the hood. I could find no leaks, no smoke from the tailpipe, no strange smell inside or wet carpets or anything like that. Car runs fine and I am still getting 25 mpg as usual.

I would like to top off the tank while I troubleshoot, but I don't have easy access to Volvo stuff. Can I top off with something else? I have Volvo stuff in there now.

It's too cold to work on the car for me right now. I hope it's something simple.

Any help on alternative coolant product and trouble shooting recommendations will be greatly appreciated.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

I replaced the cap today. The new Volvo cap I got from Tasca is teal colored instead of my original grey one. It has a slightly different valve design underneath. One thing I also noticed is my radiator fan is not coming on or at least it didn't come on in time I thought it should have. Is this a common thing? Perhaps a relay? Did I not wait long enough? After I drove about 10 miles I parked, opened the hood and waited for about 5 minutes or so. Fan stayed off the whole time. I think it should have cycled on and off at least once in that time with fully warmed up engine. Ambient temperature is about 30 F.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

You should have checked the temp gauge in the instrument cluster. No, the engine fan does not come on for quite a while. The coolant reacts better when there is pressure, which your old cap didn't supply.

Just watch the gauge for a while. If you stare at it with the engine idling, I swear it moves when the thermostat opens! With the temp around 30F, it will take a lot longer to get hot, probably 10-15 minutes at idle.

Klaus, in 15 years of owning this car I have never seen the temp gauge in the instrument cluster show anything other than dead center once the car is warmed up. Same thing now. It just sits in the center and never moves. I will try again tomorrow. The coolant level was ever so slightly lower today since I have topped it off. Not much, but down a little bit, I think. I will continue to monitor and keep updating here.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

You hopefully still had a little air in the coolant lines which lowered the level a little. Top it off to the max line when the engine is cold. When the thermostat opens, a lot of cold coolant is introduced and it takes a while to heat it all up again.

When I said my needle moved, I meant that it just moved a 1/2 millimeter lower for a few seconds as the cold coolant started to flow. If you blink, you won't see it.

Monitor it for a week or so, always when cold and in the same spot in the driveway. With luck, you should be good to go.

Klaus, thanks. I had the level above the full line last time I topped off. It was just under the entrance tot the top hose. Now it's slightly below that, but still above the full mark. I will try to catch the radiator fan going on. I think even in cold weather it should be cycling on and off pretty regularly. The thermostat is not super fresh, but it's also not that old and I am pretty sure it works fine. Still no sign of leaks anywhere I can see. I have not pulled the timing belt cover to look at the water pump, but the car only has 125K on it and is on the second timing belt. From what I have read these water pumps can last for three belts or 200K or so. Also have not checked the pistons for cleanliness. It's been too cold here (in the teens last week). Will keep an eye on the level and see what happens. Hopefully, the cap was the culprit. The new cap is a little different underneath and is teal in color vs. original grey. I am hoping I was nor driving around with unpressurized cooling system.

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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

Well, I used the car some more and the level is still the same as when I topped off. However, when I opened the hood this morning after driving a little I could hear faint hissing from the expansion tank cap. This is an original cap. Grey in color. Is it time to renew it? Could this be it? It would make it easy.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

V,

You are overdue for a new cap. What an easy fix that would be! Any sign of calcium deposits on the top of the tank? Have you kept the cap tight?

Not sure about your S70, but just replaced the cap on my 850 with a green cap from FCP Groton. Old cap was green too. Read here that green is the correct color to use. Right pressure rating. Take a good look at your hoses too as at 15 years some may be due.

J

I've been very lucky with the cooling system on this car so far. In 15 years not a drop of coolant lost and no other cooling system problems.

My grey cap is original Volvo cap that came with the car. I also have a '93 940 and had to get a new cap for that and it was green from FCP. I will order a new cap from Tasca and go with whatever is the dealer item right now. Mine says 150 kPa. I always keep it tight and really don't check it much as I said, there was never a reason to do anything there. I don't see much residue on the tank. There was some, but more in line with adding fuid, just around the opening. Not enough for 1.25 quarts of fluid to evaporate.

I will order a cap, it's $25 or something like that at Tasca. Not a big risk there and I really did not like the slight noise I heard this morning from it.

Will keep an eye on things further. I hope that's it.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

anyone consider a slight headgasket leak? check for bubbles in overflow tank when car is warm, check your dipstick. Check for white smoke out of exhaust.

If headgasket is issue. Use ccr green plastic bottle with microfiber. Fixed two cars with headgasket leaks with this stuff. One car was so bad that you couldn't even see the car behind you the smoke was so bad. Used it no problem after a year.

Head gasket did occur to me, but there is no evidence to support the theory. Oil is clean, coolant is clean, no white smoke/steam out the tailpipe. It was suggested to pull the plugs and shine a flashlight onto the piston. If it's clean and shiny, it's getting a water wash from the coolant. I have not done that yet because it's too cold and no other evidence of head gasket failure. I'll check other things first like water pump.

What is this microfiber you speak of? Can you clarify? Is this some sort of head gasket material?
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

ccr has a head gasket sealer which has microfibers in it. Believe it was originally manufactured for the military. It is liquid. You simply remove the top hose to the radiator, shake the can well and pour half the bottle in. Secure hose, run car for 20 minutes and your done.

One car needed another application, the other worked fine with only one application.

My mechanic turned me on to it and it really works. Again I had alot of white smoke, milky oil on the dipstick and big bubbles in the overflow. After a year no problems at all. Clean coolant, no smoke, clean oil. It seeks out the leaks a mends with a fiber.

Good luck

Good to know! Thanks. What is this stuff called again? For future
reference. I am kind of afraid of products that clog up parts of the
cooling system. I feel like right after the repair I would need to flush
the system to get rid of the remnants of this stuff. Still not bad if it
works for small failures. What will they think of next?!

Check out the youtube details

http://www.youtube.com/watch?v=awd2eyAbVa4

Yes, I get it how these things work, what I don't get is how the same product doesn't "pathch" places it shouldn't like small journals in the head and block. This is my fear in using these type of miracle products. I understand that if they work they are like a godsend. A head gasket on an S70 is probably close to a grand to replace and frankly, I am not sure the car is worth it at that point.

Thankfully, in my case I really do not think it's a head gasket. Simply no evidence for it. Also at 125K miles of single owner (me) life the head gasket should still be in good shape. The engine never overheated in my possession since 1998. So I think it's more likely some tiny crack or hole somewhere on the hose or the tank or even radiator. I just need to find it.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

I found a Volvo dealer about 25 minutes away, which is not bad. Bought a gallon of Volvo stuff. It costs $27/gal. I would guess Mercedes antifreeze has gone up some since you bought it for $20.

I diluted to 50/50 and topped off the expansion tank. It took a little over a quart. Went for some errands and when I came back I opened the hood, shut the engine off and observed. Nothing. No funny smells, no puddles, nothing. It is really cold right now and snowing (I'm in New England, so this is not a good time to work on a car as there are no tree shades :) ). The expansion tank loked perfectly fine, the cap was dry, the hoses are all dry and look good. The radiator looks dry. In the short amount of driving I did no coolant was lost, it seems. The level was exactly under the top hose. Will continue to monitor. Hoping it won't become catastrophic all of a sudden.

Thanks, all for the support.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

After driving it next time, pull off the upper timing belt cover and check the water pump as milanomike suggested. Very doubtful though as the waterpumps in these cars last forever (they usually go over 200k miles).

Did you check the nipple area on the bottom of the reservoir? Sometimes the nipple can develop micro-cracks. That is also where my lower tank hose leaked. Not easy to find unless you lift the tank - carefully....:)

I haven't checked the water pump yet. Too cold. I did pull the expansion tank off its bracket and looked under it. Looks good down there. I did this with fully warmed up, just shut off engine.

Also, no white smoke out the tailpipe, so I am not suspecting head gasket. Also oil on the dipstick looks good and the coolant in the expansion tank is clean.

Will keep looking. Haven't driven the car since this morning, so no news yet.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

Mercedes dealers use the same antifreeze, a Glysantin-based solution. That means, in simple terms, that it has very low silicates (to prevent precipitating deposits), and additives to protect from organic acids (important in an aluminum head or other aluminum parts).

The only difference from Volvo's blue dyed antifreeze is that Mercedes uses a yellow (or golden) dye instead, which is much more transparent and that I personally prefer -- I can see right through the M-B antifreeze to the bottom of my reservoir tank in order to visible check for any crud, rust, or whatever contamination there might be. Volvo's blue is too dark, and I don't like not being able to visibly check through the depth of the reservoir.

The downside is that M-B's price is about $20/gallon, but it's not like I'm filling up every week -- so to me, this (small price, prorated over however long before your flush again) price is well worth it. Of course, a cheaper alternative is Zerex Extreme G-05, but I don't know how much additive is in it (because of the much lower price) -- I trust M-B to have added as much as they deem necessary per their "cost is never an issue" philosophy :-) of M-B ownership (I've owned three M-B's, so I have some experience :-( with that, too.

My guess is the radiator, the age is about right for the plastic tank to go south for the winter, happen on my 97 about 4 months back. On mine, the seam was fine, but the tank was cracked and only leaked when it was hot as the crack would open up. Rare at your mileage, but you never know, is the water pump. Pull upper timing cover off and look down there, a mirror and flashlight will help. Also, consider that your upper and lower radiator hoses are like 15 yrs old. If it's the rad, I'd do the hoses also along with the t-stat. Mike

Zerex G05 is the only other coolant. Most auto parts store carry it.

You need to find the leak!

Klaus, thanks. Can I mix the Zerex G05 with the Volvo fluid? I know I need to find the leak, but at this point I need to top off the tank and watch it. It is really cold and that makes it hard for me to work on the car. Also, tomorrow is supposed to snow a lot here and I do not want be without coolant in the car.

This has never happened before with this car. I have never run low on coolant in it. First time was last week, I topped it off with the last of my Volvo stuff and now it's low again. I hope it's something simple like the expansion tank. or the cap. I see no puddles anywhere and no wet spots. Will pull the plugs and shine a light down the cylinders, but probably not until after the snow. Car runs fine and does not overheat. I really don't like having a possible coolant leak.


Thanks again.

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Vladimir
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

Hi Vladimir,

Be sure and check the vertical passenger side seam on the radiator too. Check when not too hot as it will evaporate when hot. That's where my 850's radiator went south. The only other coolant leak I've had was the lower expansion tank hose. Just replaced that earlier this year. Easy job. Thought it might have been the coolant tank leaking too, but no further leaks since hose replacement...

Naturally, check the cap and other hoses too.

Good luck finding it!
Jim

95 855 GLT 230k+

Thanks, Jim. I will do that. I am hoping for something simple like a hose.
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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers

Go ahead an mix it. When the weather warms up and after you found the reason for the coolant loss, it will be time for a flush.

I just found a dealer about 20 minutes from me. May take drive there and get the "good stuff". I just need to buy some time, but the winter is only just starting.



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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers