2008 XC70 -- Intermittent overheating and misfires

Post by **mtd240** » 21 Apr 2023, 06:42

Hi all -- my father's 2008 XC70 (~105k miles) has been having some intermittent overheating issues for a while now.

Last fall it would give him the High Engine Temp Stop Safely message if he drove in heavy traffic with the A/C on full blast for extended periods. At first I thought it was a fan issue (the fans weren't turning on), but VIDA ruled that out. So I replaced the thermostat (incl. ECT) in December -- the tabs on the old one were busted, as expected -- and it did fine until earlier this week.

It gave him the same high engine temp message, and then threw a bunch of misfire codes. I couldn't reproduce the issue - I'd probably have to drive it through traffic for a while with the laptop attached.

See the collage of screenshots below for more details from VIDA. Upper left shows some of the parameters I tracked after I started it (vehicle was already warmed up, but this was the next day, not after heavy traffic). Top right shows the timeline of the faults, bottom right shows all the codes that came up on the initial read.

A few thoughts:
1. When I hear "overheating" and "misfires" I think "head gasket". Currently in denial, since he just bought this a couple years ago, but I'll probably end up pulling some spark plugs and/or trying out a coolant gas tester.
2. Actual outside temperature was ~75F (24C), but I assume that outside temp reading is affected by sitting in the sun (which the car was), and I'm not sure outside air temperature would have this effect.
3. I am wondering if this could be due to a faulty ECT -- could that send the wrong temperature both to the ECM (misfires) and to the dash warning light?

As always, all help is greatly appreciated.

: 2008_xc70.png (359.29 KiB) Viewed 1650 times

Post by **pgill** » 26 Apr 2023, 12:06

Can you specify which engine you have?

I am going to assume a 3.2 6 cylinder Gasoline powered engine.

For the 3.2 the PCV routes the vapors (and oil if its not working) to cylinder 6 first then 5, 4, 3, 2, 1

I would look at the PCV for a 6, 5, 4, misfire. Get the aftermarket part marked with FoMoCo or get an original part

viewtopic.php?t=87687&start=210

You will also want to change the sparkplugs after the PCV.

I use Denso 4704 IKH20TT Iridium TT viewtopic.php?p=618689&hilit=denso+4704#p618689

As for the Overheating, be more specific.

- Is the coolant boiling and purging from the reservoir

- or do you just have a message on the dashboard (if its this have you independently verified the temperature)

A few items to consider for overtemperature

1. the coolant fan not running (I think you confirmed that it is running) turn on the AC and set to the coldest setting and the fan should be on

2. when the Thermostat fails it can block coolant flow if the broken parts and left behind in the engine (did you use an original Thermostat?)

3. The boiling point and heat capacity of the coolant depend on the Ethylene Glycol to Water ratio (what are you using and did you check it?)

4. The cap on the reservoir contains the pressure generate by the closed system as it gets hot. If the cap doesn't hold in the pressure then the system will overheat (purge coolant) in normal driving.

Good luck

Paul

Post by **mtd240** » 15 May 2023, 08:14

Paul,

Thanks for all of the helpful pointers.

On the misfires
I am going to change out the spark plugs today (OEM). Turns out they are original (102k miles). Crankcase pressure seems fine -- the system is still pulling a vacuum. If misfire codes come up again (they only came up the one time) I'll dig into the PCV system a bit, but the overheating is the priority at this point (if misfires are unrelated).

On the overheating:
By "overheating" I mean "the dash message pops up" -- I haven't verified actual engine temps during any of these supposed "overheating events". I did ask him to take a look last time he texted re: the light being on, and he said there was not any coolant coming out of the reservoir.

1. Correct, the fan turns on just fine -- verified via A/C on and via VIDA/DiCE tests. Next time he gets the message I'll ask him to check that the fan is running (maybe it is shutting off due to some electrical fault when it's hot?)
2. I used a Genuine Volvo thermostat. There was a tiny piece of plastic missing when I took off the old one -- perhaps that is wedged somewhere deep in the engine now? I'm putting that in "worst case scenario" for now, along with a failed headgasket.
3. I use OE coolant, 50/50 with distilled water.
4. Like I said above, he looked when it was overheated and there wasn't any coolant purging out of the system. At this point, I might need to either just grab a new cap just in case (cheaper than getting the adapter for my coolant pressure tester).

Post by **mtd240** » 15 May 2023, 10:45

mtd240 wrote: ↑15 May 2023, 08:14
On the overheating:
By "overheating" I mean "the dash message pops up" -- I haven't verified actual engine temps during any of these supposed "overheating events". I did ask him to take a look last time he texted re: the light being on, and he said there was not any coolant coming out of the reservoir.

1. Correct, the fan turns on just fine -- verified via A/C on and via VIDA/DiCE tests. Next time he gets the message I'll ask him to check that the fan is running (maybe it is shutting off due to some electrical fault when it's hot?)
2. I used a Genuine Volvo thermostat. There was a tiny piece of plastic missing when I took off the old one -- perhaps that is wedged somewhere deep in the engine now? I'm putting that in "worst case scenario" for now, along with a failed headgasket.
3. I use OE coolant, 50/50 with distilled water.
4. Like I said above, he looked when it was overheated and there wasn't any coolant purging out of the system. At this point, I might need to either just grab a new cap just in case (cheaper than getting the adapter for my coolant pressure tester).

Correction: I had the car in for an oil/trans fluid change and spark plugs, and when the A/C is switched on, only the lower of the two fans turns on. I hooked up VIDA/DiCE and tested the fans (33/66/100%), and the big fan never came on. I gave it a little push and it started up but was super wobbly.

I'm thinking it will end up needing new fans after all. Bummer, since I replaced the module recently (separately).

Post by **pgill** » 16 May 2023, 09:58

For my 2010 S80 3.2 I replaced the fan with an aftermarket continental unit and it works well. When I bought it it came with the controller but I believe that is no longer the case. I did shim the fan slightly so that it wouldn't rub. Note: if I didn't do this the plastic would have worn in eventually but the rubbing sound would have bothered me.

I bought this one CONTINENTAL FA71811

Replace the fan and let us know if you still have OVERHEAT warnings on the dash.

As for the sparkplugs please take some pictures and post them here. If the PCV is allowing too much oil to get by then it can foul the sparkplugs which will cause misfires. Take a look at the picture of my PCV fouled sparkplugs from my S80. (scroll down for the picture)

viewtopic.php?t=87687&start=200

My Niece has the S80 now and it is my understanding that it is running fine. (no check engine light)

Take care

Paul

Post by **mtd240** » 18 May 2023, 19:50

Hey Paul (and anyone else reading),

Two updates: 1) Spark plugs and 2) PS pump / Water pump / tensioner / idler / belt replacement. Apologies for the pics being slightly blurry in random places -- it's a 4-yr-old iPhone. Hoping for another couple years out of it..

1) Spark plugs were dirty, gaps were all a bit wider than spec. Original to the car, based on the FoMoCo stamp.

: IMG-2851.jpg (195.88 KiB) Viewed 1362 times

: IMG-2852.jpg (220.85 KiB) Viewed 1362 times

: IMG-2849.jpg (198.25 KiB) Viewed 1362 times

: IMG-2850.jpg (212.39 KiB) Viewed 1362 times

2) The car had a power steering fluid leak, which I narrowed down to a leaking front seal on the pump. So in addition to the radiator fan, I'm replacing the PS pump along with the original water pump and belt drive setup (belt, idler, tensioner). Fortunately the two tasks (PS pump and radiator fan) require removing the same series of items. I pulled everything off tonight (rest of the parts arrive tomorrow). The idler and tensioner pulleys were grainy and wobbly, belt is very cracked. When I pulled off the PS pump, I found the following:

: 08XC70_PSPumpAndWaterPump3.jpg (259.17 KiB) Viewed 1362 times

: 08XC70_PSPumpAndWaterPump2.jpg (231.52 KiB) Viewed 1362 times

Note that the coupling assembly appears to have . . melted? Additionally, the metal tabs on the water pump, which couple it to the PS pump and belt drive, show signs of scraping. The water pump bearing is VERY rough -- sounds like sand.

The car - 2008 3.2L (B6324S) w/ 102k miles - is beyond the 10 year maximum interval for a new belt, pulley, tensioner, and PS/water pump coupling. I would say folks should DEFINITELY replace this preventatively based on time, not mileage -- and include a new water pump. Perhaps that is a well-known practice on this forum already and I didn't catch it.

I'll put this all back together in the next couple days and update if there are any other interesting finds.

Post by **pgill** » 19 May 2023, 10:50

Thank you so much for sharing.

You have new failure modes that I haven't seen on the Volvo 3.2 (Note: it is shared with Land Rover and I own one of each)

I started a thread on the Land Rover board about 7 years ago and you are on the path to catching up on the deferred maintenance

https://www.freel2.com/forum/topic32504.html

Because I wanted to keep my LR2 3.2 for a very long time I learned everything I could about what goes wrong and I worked hard to be proactive with the maintenance.

Because of this I decided to get a used 2010 S80 3.2 for my Son and I documented what I did for the S80 here on MVS.

viewtopic.php?t=87687

Back to the problems that you are facing.

Here is what I would do if I had just purchased the XC70 that you are working on

1. Replace the Sparkplugs with original Volvo parts or Denso Iridium TT (you are already doing this I believe)

2. Replace the power steering pump - I think your pump has failed and you are planning to do this

3. Replace the water pump - I believe you are planning to do this

4. Replace the spring coupling - I think that this will come with the water pump

5. Replace the Power steering reservoir and fluid - there is a built in filter is the reservoir and I think you find that yours is blocked

6. Ignore the PCV for now - your sparkplug deposits seem very uniform

7. Be prepared to replace ignition coils if you still have misfires (an overheating engine is a possible source for coil failure)

8. Replace the Radiator Fan - I believe that you are doing this already

Some observations on the water pump to power steering pump coupling failure. The rotational motion from the power steering pump is transferred to the water pump thru the spring and its plastic coupling. You plastic coupling is completely destroyed. By comparison the coupling in my 2008 LR2 is still functioning perfectly at ~140K miles. It is possible that the blocked filter in the power steering pump reservoir has caused the failure of the plastic coupling. Yours is the first example of this failure that I have seen.

When the coupling fails then the rotation of the water pump may be erratic which is likely a cause for your over temperature.

One other possibility is that the Overdrive (clutched pulley) has seized and that the shock loading that the pulley should have freewheeled thru has cracked the plastic.

A third possibility is that the power steering fluid is not compatible with the plastic in the coupling and that exposure to a leak cracked the plastic. (Search for plastic failure crazing if you really want to know)

You are on the path to making the XC70 ready for another 10 years of faithful service.

Good luck

Take care

Paul

Post by **mtd240** » 19 May 2023, 11:32

Hi Paul -- I didn't get a new overdrive pulley. How do I test the one that is on there? My understanding is that it should turn freely in one direction but not the other. It is 100% stuck right now -- doesn't turn in either direction without some serious effort.

EDIT: Based on further reading on this READ system, it should definitely freely spin in one direction. I ordered a new one. This task is getting very expensive. I bet this is why the A/C compressor failed in early 2022, and why the PS pump and WP coupler are both torn up now. Shocked the whole belt drive system.

Will answer your other suggestions/questions in a bit, just wanted to try and catch an answer on this before you log off

Post by **mtd240** » 19 May 2023, 13:14

pgill wrote: ↑19 May 2023, 10:50
Here is what I would do if I had just purchased the XC70 that you are working on

1. Replace the Sparkplugs with original Volvo parts or Denso Iridium TT (you are already doing this I believe)

2. Replace the power steering pump - I think your pump has failed and you are planning to do this

3. Replace the water pump - I believe you are planning to do this

4. Replace the spring coupling - I think that this will come with the water pump

5. Replace the Power steering reservoir and fluid - there is a built in filter is the reservoir and I think you find that yours is blocked

6. Ignore the PCV for now - your sparkplug deposits seem very uniform

7. Be prepared to replace ignition coils if you still have misfires (an overheating engine is a possible source for coil failure)

8. Replace the Radiator Fan - I believe that you are doing this already

Yes to 1,2,3,4,8.
5: I am replacing the PS fluid, but not the reservoir -- is there an easy way to clean that filter (or at least check it)?
6,7: Will keep an eye on both of these

When he first got the car (5/2020, 75k mi) I changed the brake fluid, haldex fluid, coolant, rear diff, and did a trans fluid flush (gibbons-ish), and changed air filters. Since then I've done a thermostat and radiator hoses, and have done regular oil changes (trans fluid drain fill every 30k mi is the plan).

Some observations on the water pump to power steering pump coupling failure. The rotational motion from the power steering pump is transferred to the water pump thru the spring and its plastic coupling. You plastic coupling is completely destroyed. By comparison the coupling in my 2008 LR2 is still functioning perfectly at ~140K miles. It is possible that the blocked filter in the power steering pump reservoir has caused the failure of the plastic coupling. Yours is the first example of this failure that I have seen.

When the coupling fails then the rotation of the water pump may be erratic which is likely a cause for your over temperature.

One other possibility is that the Overdrive (clutched pulley) has seized and that the shock loading that the pulley should have freewheeled thru has cracked the plastic.

A third possibility is that the power steering fluid is not compatible with the plastic in the coupling and that exposure to a leak cracked the plastic. (Search for plastic failure crazing if you really want to know)

I am thinking the coupling failed due to Option #2: overdrive pulley seized. See previous message - I think this failure busted up everything in the belt drive, starting with the A/C compressor in mid-2022.

Post by **pgill** » 22 May 2023, 10:47

The filter screen in the reservoir can be seen in this link

https://landroverforums.com/forum/lr2-3 ... mp-103033/

I highly recommend that you change it.

You can use an inexpensive aftermarket part to save some $$$.

Make sure you use CHF 202 or CHF 11S power-steering fluid.

Do you gave the tool needed to remove the overdrive pulley?

https://www.freel2.com/forum/topic33867.html

You are on the right path. Keep going.

Take care

Paul