Losing coolant but can't find a leak

[Ethan5150]

Hi folks, I have a 2006 S60R that's recently had coolant problems and I'm hoping to get your thoughts.

When I first got the car about 9 months ago, my mechanic noticed the expansion tank was getting ready to crack so I replaced it (OEM). Then about 3 months ago, the hose blew off the top of my radiator at which point I discovered the neck had apparently long since broken off so there were no longer ribs keeping the hose from slipping off - it was only getting like 3/4" purchase. This happened road-side so I did my best to get the hose back on, but it happened again a few days later and I realized I'd need a better solution. I then undertook to "repair" the neck by following the writeup here. It seemed to work for a while, but I occasionally noticed a small drip coming from my fix - usually after a long highway drive. I would top off the tank every time the "coolant low" message came on (usually a quart or less) but very shortly thereafter one of the main hoses running into the firewall blew out hard and left me stranded in the middle of nowhere. My mechanic replaced both of those hoses with OEMs I got from FCPEuro. The day after he replaced them I went for a drive and after a while, developed a leak at one of the clamps he had put on (he had done a pressure test before sending me on my way). So he tightened down the clamp and that fixed the leak. However, I'm still losing coolant - and I no longer see it dripping from my radiator neck fix (although I felt like I may have smelled it today, even thought I couldn't see anything). I added coolant twice today (not much, maybe a half quart each time.

Some additional details that may be of use:

* When I open the expansion tank when the engine is hot, coolant immediately rushes back in and brings the level up quite a bit. Is this normal?
* Ever since I purchased the car 9 months ago, it's stumbled a little when I first start it, which clears after maybe 15-30 seconds. My mechanic's assumption was it probably needs coils... but could this be a cracked cylinder?
* I'm not seeing any white smoke coming out of the tailpipe.
* When the coolant hose blew out and left me stranded, it happened right after I floored it to make a pass on the highway.

Am I screwed?

[yanga001]

You most likely have a slightly compromised head. I have heard the gaskets on these are much better than the old ones, but the heads can develop a slight warp. Some users here state that the open deck design can result in head failures after you floor it on a cold engine.

I had the exact symptoms on my 98 V70. It got worse after a coolant pipe blew off and i limped it to a nearby property with honda coolant. My symptoms were as follows:
-Hard, rough starts after the car was sitting or if it was hot. Misfires would occasionally occur on 2 cylinders but it would later clear up
-When i scoped my engine, i believe 2 of the cylinders were pretty clean
-I would consistently see bubbles coming from the smaller hose when i angled the expansion tank to cover said hose with coolant.
-In that case, i was able to fix it with head gasket sealer (blue devil) but that failed when my car froze solid on the highway (probs not an issue for you).

However, the car would still run and in hindsight, it probably had a breached head for upwards of 2 years. My car never got to the red temperature when i limped it home(drove till it went above normal temp then turned off the car), however it was still enough to do damage.

An R block is probably a harder one to find. This may be your best bet.

If you do not see coolant in oil or coolant in trans fluid or vice versa then you are a good candidate for a good quality head gasket sealer. The solution may work for a while or may fail sooner but it is better than nothing. I was out about 150 cad after buying the sealer, a coolant flush, and 3-4 bottles of coolant.

[dikidera]

If the s60r is the 4t5 with the 81mm bore, a cracked cylinder is unlikely, but these cars do blow gaskets and warp the block as well.

Test the coolant for exhaust gasses. If yes, time for machining the head and block deck.

[Ethan5150]

Thanks for the response yanga001,

I just did a block test and it came back positive for a leak. Most of what I've read about this suggests it's a failed cylinder wall, but you're saying it could be a failed head gasket?

Is there an easy way to test this?

I'm not sure how I could tell if coolant had gotten into the oil - would this be easy to see?

[MoVolvos]

Thanks for the response yanga001,

I just did a block test and it came back positive for a leak. Most of what I've read about this suggests it's a failed cylinder wall, but you're saying it could be a failed head gasket?

Is there an easy way to test this?

I'm not sure how I could tell if coolant had gotten into the oil - would this be easy to see?

.
I'm wonder if you can employ this method in the beginning with our Volvo. May have to fill the coolant reservoir all the way to the top?
.

.

[dikidera]

Thanks for the response yanga001,

I just did a block test and it came back positive for a leak. Most of what I've read about this suggests it's a failed cylinder wall, but you're saying it could be a failed head gasket?

Is there an easy way to test this?

I'm not sure how I could tell if coolant had gotten into the oil - would this be easy to see?

The 81mm bore B5244T5 block is very sturdy, if your S60R is the 256hp one, or the engine code is B5244T5 then it is most unlikely the cylinder is cracked. Probably just a failed gasket, but if and when the head is off, it would be wise to verify it is not the cylinder by visually inspecting the cylinder walls.

But again if your engine block is the one with the thick cylinder walls, I really don't think it is the block, but just the gasket. The head should be machined flat and the engine block tested with a straight edge for warpage.

[Ethan5150]

Dikedera,

I'm confused. I have a 2006 S60R Base. Were there multiple engines for this car? I thought the 300HP was standard. Everyone else is saying this is the engine with thin cylinder walls that should have been shimmed. See here:

https://www.swedespeed.com/threads/losi ... ak.678624/

and here:

https://www.swedespeed.com/threads/cyli ... ck.442833/

and here



(There are countless other posts about this too.

What am I missing?

[dikidera]

It seems Volvo did not use the better block in the later Rs? If so and you have the thin cylinder wall block then yes, without shimming it is likely to crack, if it hasn't already for you.

In any case only when the head is off can you verify if the crack has started or not.

[RickHaleParker]

The 83mm bore 2.5L is standard for the R version. These like to crack cylinder walls.
You keep saying Base. I think that is creating uncertainty about what you have. An R version is not Base.
Post your VIN number and we tell you want your car came with.

Keep in mind because the 2.5L likes to crack cylinder walls they often get replaced with a 2.4L.
Get the numbers off the block and post them also.

Dikedera,

I'm confused. I have a 2006 S60R Base. Were there multiple engines for this car? I thought the 300HP was standard. Everyone else is saying this is the engine with thin cylinder walls that should have been shimmed. See here:

[dikidera]

The difference between 2.4l and 2.5l is so negligible, it likely gets buried under the additional boost you can add to your car when it is shimmed

I know an R guy with 450hp at the crank with just a shimmed block.