Diagnosing low coolant in 2001 V70

[abscate]

Unless you can contact the servicing dealer, you are driving a 200k timing belt - a pretty much well-armed grenade being held with dental floss. Drive it carefully. Its a 1500 USD repair if the belt breaks, doing the work yourself.

[prwood]

Unless you can contact the servicing dealer, you are driving a 200k timing belt - a pretty much well-armed grenade being held with dental floss. Drive it carefully. Its a 1500 USD repair if the belt breaks, doing the work yourself.

I contacted the servicing dealer, who serviced the car up until 2007, and they didn't have any record of changing the timing belt. They did helpfully give me the summary service record, although they couldn't release the detailed records as they had the customer's personal info.

From 2007-2010, it was serviced at a Sunoco, so I suppose they might have service records, although I'm less hopeful of their record-keeping.

Also, I suppose there's a chance that, if it was serviced, the servicer might have written the date on the timing belt or elsewhere, so I guess I can check for that.

But it would probably be safest to assume that it hasn't been changed at all, and change it as soon as possible.

Still not sure about the cause of the low coolant.

[jimmy57]

not enough to account for the 2 gallon loss on that heater core view. It has some minor o ring leakage. The cylinder crack is not usually seen by compression test but can be found by getting engine hot and then pressurizing coolant system t0 15 psi. Then remove plugs and spin engine over with starter. You can jumper the two perpendicular connection in starter relay base and crank engine over key off that way without fuel or spark. The offending cylinder will often have puffs of steam when the pistons push out through spark plug holes. An engine is the fix. You can't fix the crack if that is what it is. Head gaskets rarly let go on thee engines unless it has been melting the plastic covers hot. Then the head is warped and an engine is also the fix as the machine shop work and parts will go over used engine price quickly.

[prwood]

by getting engine hot and then pressurizing coolant system t0 15 psi. Then remove plugs

Is it safe to remove the plugs while the engine is hot? I thought you were supposed to wait until the engine was cool to remove the plugs...

[prwood]

Yeah.... so... quick update. I think I found the cause of the leak, and ... it's probably my fault. But, backing up a bit...

This evening I borrowed a coolant system test kit from Advance (very nice kit btw, very solid and had the exact adapter for the Volvo expansion tank and instructions for testing using the expansion tank). I ran the basic cooling system test using their instructions on a cold engine. The expansion tank cap says 150 kPa, which is 21.75 psi. I started pressurizing the system... things looked ok up to 4 psi, but by 6 psi I could already see a trickle of fluid starting to come out of the bottom of the connection between the upper coolant hose and the fitting on the radiator. I took it a bit higher, at which point fluid also started coming out of the top of the connection, but it wasn't even halfway to 21.75 psi before the fluid was just gushing out.

The upper coolant hose is brand new, installed by me last year... but I'm guessing that the hose clamp was insufficiently torqued by yours truly. I always tend to be a bit skittish about over-clamping, but I guess in this case I should do a bit more.

That being said, I don't want to just assume that the tightness was the issue. Here are some photos showing the end of the hose and the fitting on the radiator. The radiator fitting seems like it's experienced damage of some sort - the plastic molding around the metal sleeve is chipped around the end, but I can confirm that it has always looked like that since I bought the car, and it hasn't always had this coolant loss issue. I have taken it off fairly frequently in the past year or so, as a lot of the repairs I've done are easier when that hose is out of the way. I did just see a video where someone moved it by removing the Torx bolts holding the thermostat hose mount and swinging the whole thing out of the way... man, that looks way easier. Will have to try it next time.

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In any case, I'm going to try tightening the hose back down, much more so than I did the last time I installed it. I don't know if there's such a thing as torque specs for hose clamps, or if a torque wrench would even be able to measure properly on a hose clamp, so I'll just have to do a little trial and error. I was thinking that, before I filled the coolant back up, I would reattach the hose, tighten the clamp, and then use the pressure tester to see if I could get it up to 21.75 psi without the hose popping off. Dunno if that's a great idea or if there's a better way to gauge how tight to make the clamp...

The other thing I'm pondering is why I never saw any evidence of this before now. I have a few theories:

1. Due to the looseness in the upper radiator hose, the pressure in the system never built up high enough to cause a visible leak.
2. The leak just wasn't happening while I was looking. Maybe it happened while I was driving and dissipated quickly enough that I didn't see any evidence.
3. The leak was a tiny trickle at the times I *was* looking, and I didn't notice it. And what fluid did come out was caught by the drip tray underneath the radiator.

Let me know if you have any other thoughts.

[jimmy57]

If they are Uro hoses then get something else. They will leak again. I think they are made of licorice. Glad it is hose leaks and not the gloomy other things.

[jonesg]

Good job tracking that down.
With the alum reinforcing sleeve inside the plastic neck on the rad you can go quite tight on the clamp, the clamp will cut the hose before the neck collapses.

My guess is the hot pressurized fluid damaged the lip on the neck of the rad....and I should know , I'm a baker.

[prwood]

If they are Uro hoses then get something else. They will leak again. I think they are made of licorice. Glad it is hose leaks and not the gloomy other things.

Any recommendations on the best hose? In this case it seems like it wasn't so much the hose's fault as it was mine for not clamping it down enough.

[prwood]

Good job tracking that down.
With the alum reinforcing sleeve inside the plastic neck on the rad you can go quite tight on the clamp, the clamp will cut the hose before the neck collapses.

My guess is the hot pressurized fluid damaged the lip on the neck of the rad....and I should know , I'm a baker.

Once I had the pressure test kit, it wasn't hard at all to track down. It was pretty obvious seeing the coolant squirt out of the hose!

I am a weakling, so what I consider to be "very tight" is apparently not tight at all by normal standards. When I reattached the hose, I used the pressure tester to gradually bring the system up to pressure to see if it was tight enough. Lo and behold, it started leaking again, so I went and tightened down the hose even further, and eventually it was able to hold at 21.75 psi for two minutes! So it seems like everything is good there.

That being said, I do have a few follow-ups:

1. Is there ANY good position to put that hose clamp in? No matter how I position it, my wrenches and sockets can just barely fit, and definitely not with any wiggle room.

2. I also pressure tested the coolant expansion tank cap. The weird thing is that the cap is labeled with 150 kPa (21.75 psi on the gauge), which is what I used when I pressure tested the system... but when I pressure tested the cap, it only held up to 15 psi (only ~103 kpa). If I tried to go over that, it started squealing and the pressure dropped back down to 15. My impression was that the cap should hold up to the pressure printed on it, but maybe that's not the case? Either that or the tester wasn't working correctly?

3. When I went out to test drive after reattaching the hose and topping off the coolant, I stopped at one point because I was getting the "coolant low" warning. I sort of expected it because there are usually air pockets trapped in the system after having it disconnected like this, and you have to top off a few more times. HOWEVER, after I topped it off and started the car back up, I started having a NEW problem, which I'm not sure is related, but... the car started driving very slowly, and I got a dashboard warning message "Engine System Service Urgent". I was able to limp home. When I got home I pulled the engine codes, and I had a P1237 "Cyl 1 - Fuel Inj Circ. Open Circ." and a P0121 "Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance". I also read the live data from the engine and saw that the throttle position was staying at 20% no matter what I did with the pedal. I have started to research this here and elsewhere, and most of what I'm reading about P0121 points to issues with the ETM. I removed and cleaned it last summer, so I'm not sure if it needs to be cleaned again, or if I need to do something else. The P1237 I read was for the turbo control valve... not sure if that figures into this somehow...

[jonesg]

1. clamp,
if theres room , it's not illegal to double clamp iffy hoses.
For tight spots re/ clamps I use an elec ratchet wrench, or a wobble extention .

2. Pressure cap,
don't know but they are cheap to replace, real cheap if you go to the junkyard in Billerica.
Hollands Pick n pull have a lot of V70/S80 wrecks.

3. Limp mode,
I just had that , it was a fuse in the engine bay.
Accelerator position sensor and Ebox cooling fan , that was fuse 8 in my case.

.. don't know if low coolant warning triggers limp mode, it would make a lot of sense if it did.