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Hoping someone can help with my.mystery coolant loss

5K views 40 replies 18 participants last post by  ElementR 
#1 ·
So I've read a few threads on here in regards to coolant loss on the R 2.5 blocks and I'm getting into the same boat.
Lately I've topped off the coolant to have it be below half about 4 to 6 days later.
Ive checked the heater core hoses in the firewall and it looks like there is a LITTLE white staining, but not enough to talk about the coolant loss I'm seeing, I took out the center console to check the heater core and it's not leaking there either.
The underside of the coolant cap has a TINY bit of white residual on it but still not consistent with the loss I'm seeing.

Ive read about the dreaded cylinder wall cracking but I would expect to see white smoke on startup denoting coolant escaping. However i see white smoke on cold morning startups just from the cold air and on warm mornings, no smoke so that leads me to believe that is not the issue either..

I'm hoping someone on here who is more experienced with these cars can chime in. My next test is to pressure the cooling system and check the radiator for a minute crack but I dont see any coolant dropping on the ground.




Cheers


Colton
 
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#2 ·
Could be a head gasket. If it got the slightest bit hot it could have blown.
Did your gauge EVER go above the middle?
Coolant should be tested
 
#3 ·
Oil cooler, turbo, thermostat/sensor housing area are three areas that are hard to track down because it generally burns off instantly. Mine wasn't losing coolant at an alarming rate, but when I pulled the thermostat housing to replace it preventatively there was a tiny leak. Eventually I'll send my R off to get the engine "bulletproofed" along with a few upgrades, but until then its all Stage 0 maintenance and enjoying it.
 
#6 ·
So I've read a few threads on here in regards to coolant loss on the R 2.5 blocks and I'm getting into the same boat.
Lately I've topped off the coolant to have it be below half about 4 to 6 days later.
Ive checked the heater core hoses in the firewall and it looks like there is a LITTLE white staining, but not enough to talk about the coolant loss I'm seeing, I took out the center console to check the heater core and it's not leaking there either.
The underside of the coolant cap has a TINY bit of white residual on it but still not consistent with the loss I'm seeing.

Ive read about the dreaded cylinder wall cracking but I would expect to see white smoke on startup denoting coolant escaping. However i see white smoke on cold morning startups just from the cold air and on warm mornings, no smoke so that leads me to believe that is not the issue either..

I'm hoping someone on here who is more experienced with these cars can chime in. My next test is to pressure the cooling system and check the radiator for a minute crack but I dont see any coolant dropping on the ground.

Cheers

Colton
most likely cracked sleeve...any miss-fires in the mornings? or after sitting for a while?

as far as checking for it ...open up the coolant tank while it is cold and start the car, if you have air bubbles coming up in the tank = cracked sleeve...head gasket is rare unless you overheated at some point.
 
#8 ·
@Dougy
I will test the coolant bottle check once I get out of class, that is by far the easiest way I have ever rear to test that! Thank you!

In terms of misfire, I have had a few HOWEVER before anyone mentions that being a side effect of the cylinder wall you have to realize i am on 100% E85 and that fuel HATES cold weather starts, the density causes some cold start issues and we had some mornings where the night temps were well below 20*F and in the morning it was still below 30*
 
#9 ·
I've experienced or seen a bunch of different ways that these cars can lose coolant:

1. Radiator core started leaking at the end tank (crimp is probably coming loose), very slow leak, only detected because I could see dried coolant on the end tank, fixed by replacing radiator.
2. Thermostat housing started leaking, only when hot- small drip when hot, no leaks when the engine was cold, fixed by replacing thermostat housing.
3. Water pump can leak, especially if it is over-tightened- haven't experience that myself, but I've seen it.

Those are all failures that don't cause a milkshake in the coolant or the oil, don't have an easily detectable leak.
 
#14 ·
ill take a look at those, ill be home next week and will be pressure testing the radiator since that seems like a likely possible culprit IF the resevoir doesnt bubble when i start the car today. (fingers crossed).
Ive checked the oil for milkyness, both under the cap, and the dipstick
 
#12 ·
#17 ·
For me the radiator end tanks aways leaked and you could see small droplets weeping down the sides

Sent from my SM-G970U using Tapatalk
 
#18 ·
Pressure test is quickest way to find a leak. Combustion gas test of coolant may show an issue but may not and that doesn't mean you don't have an internal leak as it could only be occurring under boost and combustion gases dissipate before test can detect any.

Do you smell any coolant inside particularly when heat is on? You can get a very small leak at the heater core and never visually detect it. It takes only the tiniest leak to detect it by smell.
 
#22 ·
@Dougy I let it run between 4 to 6 min and nothing so it shouldbt have been a time issue thankfully. I'll check the others and go from there.
My backup is a buddy with an s60r with an m66 and 4t5 block that I can swap in but I dont really have the money even though I really want to do it 😅😅😅
 
#23 ·
:thumbup: if you saw no air bubble/bubbles come up...you have no crack/s...if one want to speed up this process have a friend rise the idle to 2000 rpm, the end results will be the same especially when the engine is cold.
 
#24 ·
My R had a distorted cyl 4 liner. The bore is around 83mm through the sleeve except at the top, where a gap is between the cylinders. It opened up to 83.2 there but no cracks. Coolant was getting in that cylinder. Only symptom is slowly disappearing coolant, and very rare misfire after sitting 1-3 hours, never when cold. No bubbles in the reservoir ever.

A crack in the cylinder is much more severe. One of my friend had that. He had a pressurised cooling system even when cold, at warm engine opening the reservoir the coolant line came up from low to the top of the filling piont.

So the clearest test is to remove the spark plug, and check for a clean(er) piston. Mine had that, even had a little coolant on top.
 
#26 ·
Mine wouldn't lose any coolant until it was to operating temp.

I had a specialist troubleshoot a whole bunch too. No hydrocarbons in the coolant. No bubbles in the coolant. At the end of the day, he figured it was the headgasket. So he popped it off and found the ugly truth.
 
#31 ·
So I've read a few threads on here in regards to coolant loss on the R 2.5 blocks and I'm getting into the same boat.
Lately I've topped off the coolant to have it be below half about 4 to 6 days later.
Ive checked the heater core hoses in the firewall and it looks like there is a LITTLE white staining, but not enough to talk about the coolant loss I'm seeing, I took out the center console to check the heater core and it's not leaking there either.
The underside of the coolant cap has a TINY bit of white residual on it but still not consistent with the loss I'm seeing.

Ive read about the dreaded cylinder wall cracking but I would expect to see white smoke on startup denoting coolant escaping. However i see white smoke on cold morning startups just from the cold air and on warm mornings, no smoke so that leads me to believe that is not the issue either..

I'm hoping someone on here who is more experienced with these cars can chime in. My next test is to pressure the cooling system and check the radiator for a minute crack but I dont see any coolant dropping on the ground.

Cheers

Colton
I had a strange leak on my V70R, I put dye in the system and had to wait a few weeks until I found the issue. It was the thermostat housing and the seal on the block weeping slowly in some cases but a lot more other times.

Its not always a cracked sleeve.
 
#33 ·
Update so hopefully someone can chime in. I'm still experiencing the loss.
I'm still experiencing the "mystery" coolant loss and for the life of me I cannot find it. Over the past week my coolant bottle has gone from the max line to just above halfway between max and min. There is NO visible leaks and so far what I've done is.
1) tested for bubbles in the coolant system by removing the cap and cold starting the car to see if any form which there was none.
2) block tester at the coolant bottle and there was no change in the fluid color no combustion gasses in the coolant.
3) pressurized the coolant system to 21psi and other then a TINY bit of pressure loss due to the cap fitting there was no pressure loss and no visible leaks at the radiator etc.
4) visual inspection of thermostat housing, heater lines, etc when the system was pressurized.
5) checked the heater core inside the car behind the radio no leaks
6) saw no leaks at the radiator.
7) I get a misfire at cold temperatures but I also run 100% e85 and that fuel HATES cold startups. It also hasnt misfired since the caf is currently living in a garage so that cant be it either.
8) I get a bit more whiteish smoke at cold start but yet again e85 typically causes more condensation and my oil is clear of any milky crap that would show coolant getting into it.

Hopefully someone may have an idea!
 
#34 ·
Sorry that you can't find it, but if you're holding pressure and have no combustion gases in the coolant and no coolant in the oil, that's a good thing.

You won't see the radiator leaking unless you take a very close look- have you pulled the undertray and checked the whole radiator? Very little access without pulling stuff. I couldn't really see my end tank leak until it lost enough to leave a residue on the side- that took years. I've had a similar loss for many years and no issues.

The thermostat housing leaks when it is hot, not cold- you won't see it until the engine is warmed up and the coolant hot- I had that issue and only saw it seeping while hot because I got a low coolant warning, pulled over, popped the hood and saw it seeping slightly. That hose is a serious PITA to remove- make sure you clock the clamp properly or you'll never be able to tighten/loosen the hose properly.
 
#35 ·
Probably a slow leak in a tough to spot location. If you apply pressure to a system that is not leaking, you should be able to walk away for a couple minutes, come back and see no decay in the value on the gauge when you left it.

Stant makes a lot of OEM caps and thermostats. They also sell testers. You can read more about how to use one to diagnose the source here...

http://www.stant.com/files/5914/0979/7194/Pressure_Tester_Installation.pdf

If the car is driving and running well, I wouldn't fret much. Slow leaks can be difficult to find and not necessarily internal.
 
#36 · (Edited)
if it misfires at start up after sitting a while = cracked sleeve-s ... look up with generic obd2 tester which ones misfires , pop the coil-s , plug-s and scope it- them... you will see coolant in the chamber-s and that is why it misfires.


pressurize the coolant system and scope it and you will see the coolant seeping in from the crack.
 
#37 ·
Or wad up a sheet of paper towel and drop it into the suspect cylinder when you pressurize it and it ought to soak up any coolant... if it's a cracked cylinder liner. I'm not much of a gambler, but can see this going either way: cracked liner or external hard to spot leak.
 
#39 ·
Hello i have had the same exact issue and it was definitely a cracked sleeve.

I recommend a exhaust gas in coolant test. Leave it on the engine for 30 minutes-1hour depending on how big your crack is it will turn your test fluid from blue to yellow. Sometimes it will take longer depending on the severity of the crack. If it even turns a little yellow you have a crack.

Morning starts would stumble misfire also.
 
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