[2001 V70 2.4T] Occasional coolant reservoir boilover

[prwood]

I picked up the hose today, and I can get it to bend into roughly the right shape without too much effort, but it definitely wants to snap back into a straight-ish line. I'm a bit concerned that the strain of keeping it in a bent position over time might be an issue for the integrity of the hose (which I'm assuming is why the OE piece is molded into that shape in the first place). Maybe it will soften up a bit once it's got hot coolant going through it?

[abscate]

It might last only 5 years vs the 20 years the Volvo parts last. Make a note in the log to inspect it each year, it’s going to seep before a major failure so your coolant level monitor will also warn you.

[pbierre]

It's possible your radiator is not shedding heat efficiently. It's usually clogged internal coolant flow, or poor airflow.

Have you checked the front surface of the radiator for flattened fins? I've seen some cratered over 50% of surface area.

Your running temp. is too high. Normal is 85-90C. When you can dump heat via the cabin heating system, that suggests that your radiator is the weak cooling component.

[prwood]

It's possible your radiator is not shedding heat efficiently. It's usually clogged internal coolant flow, or poor airflow.

Have you checked the front surface of the radiator for flattened fins? I've seen some cratered over 50% of surface area.

Your running temp. is too high. Normal is 85-90C. When you can dump heat via the cabin heating system, that suggests that your radiator is the weak cooling component.

Interesting thought. I installed a new radiator in August 2018 at 238,000 miles because the old one was leaking at the top inlet. It's now at 262,812 miles, so that's 24,000 miles driven on it (plus likely a considerable amount idling in traffic, parking lots, and driveways). I got this CSF model from RockAuto:

https://www.rockauto.com/en/moreinfo.ph ... 19&jsn=309

It has a two year warranty which I guess would have run out this past summer, which is around when I started seeing issues with boilover. I'm hoping that's a coincidence, and not a sign that the quality is so bad that it only works just past the end of its warranty. I'll give it a visual inspection though just in case. I definitely haven't seen leakage from any part of the radiator or from any of the lines connected to the radiator. When the engine cooling fan runs, I can definitely feel plenty of heat in the air being blown away from the radiator, so I feel like the radiator is at least nominally functional.

I'm also wondering if a turbo engine like mine would be expected to run at higher temperatures than normal?

[abscate]

It actually runs at lower temperatures

The thermostat on a turbo car is nominally 87F and 90F on a NA car. Thats a nominal difference, though.

If you used fresh coolant when you did the radiator, I doubt you plugged it. You can use one of those cool IR temperature guns to check the temperature onthe radiator to make sure it is uniform, then get one of us to do the same to compare. I know you hate gathering data before making a decision.

[prwood]

It actually runs at lower temperatures

The thermostat on a turbo car is nominally 87F and 90F on a NA car. Thats a nominal difference, though.

If you used fresh coolant when you did the radiator, I doubt you plugged it. You can use one of those cool IR temperature guns to check the temperature onthe radiator to make sure it is uniform, then get one of us to do the same to compare. I know you hate gathering data before making a decision.

I got an IR temperature gun and took some readings last night after having driven the car around a while. I parked the car and idled it in my driveway with the heater and AC turned off, and also with them turned on so as to trigger the engine cooling fan. I took readings in various places and here's what I found:

- Reading taken off the top of the thermostat housing tracked the ECT within 1-2 degrees F (195F in this example).
- Readings taken off of other various metallic surfaces on the engine head and block were pretty close to the ECT as well.
- Reading taken off the upper coolant hose was about 20 degrees F cooler than the thermostat temp (175F) which I expected since the rubber is insulated.
- Reading taken off the lower coolant hose was about about 20 degrees cooler than the upper coolant hose (155F) WHEN the fan was running, but was about the same as the upper coolant hose when the fan was NOT running.
- The readings I took everywhere else were quite steady, but the readings I took off of the radiator were all over the place. I took the readings off of the radiator fins, shot between the fan blades while the fan was stopped. I'm not sure it's really a reliable measurement. It was bouncing anywhere from 115F to 165F and everywhere in between, whether or not the fan was running. I'm wondering if this is due to the multifaceted and reflective design of the radiator.

Conclusions and/or questions:

- Is there a better way to take a reading from the radiator?
- Since the hoses before and after the radiator were both showing a similar level of heat, my assumption is that the radiator is not blocked and coolant is flowing through it.
- How much, if any, is the radiator expected to cool the coolant if the engine fan is not running and the car is stationary? I get that the point of the radiator design with the multitude of metallic fins is to have as much surface area exposed to the air as possible so as to dissipate heat, but it seems like without the cooling fan, or without the force of air as the car is driving, at best it's keeping the temperature at equilibrium. With the engine constantly running and reheating the fluid, and no force actively drawing heat away from the radiator, it doesn't seem like there's that much opportunity for it to cool down.

[abscate]

In Northeast winters it is not uncommon for me to idle with the hot engine and never hear the fan come on. The radiator has enough passive convection and radiation to cool below the threshold for fan turning (about 97C?) in my experience. I’m 99%confident on this.

[prwood]

Well, I took the day off work today to tackle replacing this hose, since this is about as warm as it's going to get anytime soon. I'm not confident that the replacement hose I got is going to do the job, or that I'll even be able to reach it without taking the whole PCV breather hose assembly off, but I'm going to give it a try anyway. Wish me luck!

[prwood]

So far so good! I was able to disassemble things to the point where I could get to the leaking hose. Here's a photo of everything at maximum disassembly:

Removed strut tower crossmember, charge air pipe, top engine mount, side engine mount carrier plate, fresh air pipe, moved fuse box and battery cables out of the way, also removed camshaft position sensor outer housing which I wasn't expecting but was easy enough and made access and visibility much better.

Here's what the bad hose looked like:

Both ends were badly cracked. The end going into the block was practically ready to separate on its own. The rubber had gotten incredibly rigid. This feels like really bad quality to be in this condition after just over two years. I definitely would not recommend the IPD aftermarket PCV hose assembly. I checked the other end of the hose, the one coming from the thermostat assembly into the banjo bolt on the intake manifold. Here's how it looked:

Pretty bad, huh? Again, this is just past two years since it was installed. There doesn't seem to be much, if any, leakage coming from this hose YET, but I'm not holding my breath. I definitely wouldn't recommend IPD's aftermarket PCV hose assembly, based on the low quality I've seen in multiple instances.

Here's how the new hose looks installed. It's much longer than the original, but I was able to route it so it wasn't in the way of anything and I didn't have to bend it too far. The hose is a Gates "safety stripe" heater hose and seems like very good quality, so I'm hoping it will last for a while.

I was able to do about an hour's worth of mixed street driving and idling, while running normal climate control modes. ECT still got up pretty high, up to 221 at one point, but it did seem to come down on its own without having to resort to running the heater/defrost cycle to dump heat, and there was no apparent coolant loss.

I haven't done any highway driving yet, so that will be the next thing to check.

I'm wondering if it would be worth troubleshooting why the engine is running so hot in the first place - based on past experience, it typically seems to run between 195-205F for the first 45 minutes or so, then it seems to hit some condition that takes it into the 205-220F range.

[prwood]

Did a highway drive last night, followed by city driving, followed by idling. No coolant loss, although by the end you can see that the last bit of idling caused the ECT temperature to rise into the 200F+ area and settle into a a roughly 205-210F heating-cooling cycle. I'm wondering if this temperature at idle is cause for concern.

But again, no coolant loss, which was the initial issue I was trying to solve.