02 XC70 - The repairs have started

[scot850]

Been a while, but I have been working on this project when limited time over the last week or so has been available. Also I have been waiting for parts both new and used to try to resolve hopefully at least one of the coded issues the car is throwing, including occasional rough running verging on misfiring.

Last time I reset the codes, immediately after starting the car it ran ok for a short run just to confirm it started. 2nd start the rough running returned immediately. Codes also retuned at the same time. 5 of the 10 original ones had been removed, but 5 returned. Those are listed in earlier or linked posts.

I had no clear way forward, so tackled the (exhaust) cam signal issue and the throttle body (TB). First one as I saw a clearance Intermotor cam sensor and crank sensor really cheap for around $55 CDN from Rock Auto. These parts were delayed, but the plan was to compare the parts with the original as information on how to test manually without Vida was not clear or available. Jonesg has been a great support which is appreciated.

I also had an option on a low mileage TB from a car that had only run 5000km after fitting before being totaled. For $90 CDN (about $68 US) it was an aftermarket Vemo part that even if not used can be a spare for our son's 06 XC70. Took a bit to get the part but I took the delay time to remove and clean all the parts that had to be removed for the cam position sensor to be removed as well as the TB. I also got lucky that my mechanic buddy also had a used TB I could borrow. There was confusion if software was an issue as well as part numbers. That was caused by some 02 cars had the older P80 style ETM's and they changed over to TB's. This car has a TB so no software was needed.

The Cam sensor area inside the cover on the end of the exhaust cam had evidence of oily residue. I also noticed that was original cam sensor in the car had provision for an o-ring seal but there was none which may have allowed dirt or leaking oil from above to get into the sensor area. The replacement sensor from Rock Auto turned out to be an older part number Volvo labelled part. Jury is still out on if it is a new part or someone being cute returning a faulty part. I really only wanted a comparator part for electrical testing to see if the original part was good or bad. Turns out they both tested the same. I did need to buy some needle probes to probe the cam sensor wires at the connector as they are sealed. They worked well. So, I decided to refit the original part as it was either good or bad as per the 'new' part.

I refitted the sensor and all the other parts including the bracket for, and the top torque mount, the strut brace and the air box lid and pipe to the turbo (to give room to get bolts out of brackets to get to the cam sensor).

With that refitted, I turned to my nemisis the TB. If you have read my earlier notes you will know why this is!

While I had been waiting for the 'new' TB I had tried testing and comparing the original and the loaned TB's. The original sounded like a bag of bolts and grated for a while on start up, and also on shut off. The loaner was quiet but sis not move on start up or make any noise but sis move the flap maybe 30 degrees on switching off. My mechanic buddy told me that the small motors in the TB's can strip the plastic gear teeth. So I decided to open them both and compare. The original is not the original to the car. It is a Bosch replacement unit. It was actually really clean on the inside with a little dirt but clean. I removed the motor and noticed the motor was fairly clean but the bearings were dry. I used a drop of light oil on either end and reassembled. My view was to see if any improvement was noticed and as a learning exercise. I did the same to the loaner which showed more signs of wear on the plastic teeth and was dirtier.

I then got the 'new' one and connected each in turn to the car and cycled them on the ignition. The all worked identically, even the original which was now totally silent too!! What I did notice was one of the 2 tiny and totally flimsy clips for the connector to the TB was partly broken and would not clip in place. There was no easy source for a new connector so I decided to just refit the original now silent TB and wire the connector in place using the one clip that was still good.

Refitting the TB was a pain. It works on the Volvo repair process of you can see what you need to do but not access it, or not see what you are doing but work on touch only. I fitted a new TB gasket I had, after cleaning the inlet manifold surface. Torqued the bolts to 10Nm as spec'd. Then I built up the energy to tackle trying to fight the stupidly designed TB intake pipe. Like the last time my arms are shredded and bruised but eventually I got it on and all the other pipes and connectors installed.

I h ad to stop to help a friend with his sickly Subaru Imprezza (his kids car) to try to identify an electrical issue. Once we did that as I had the Autel out anyway, I decided to clear the codes on the XC70 with a plan to try it today. I couldn't resist. So I fired the car up and it purred. I only ran it for a short time as the garage fills with fumes quickly. NO CODES!!??

Switched off and retired bruised and battered. Did not want to ruin the moment with a 2nd start in case codes reappeared.

Today, I tried the car again. Last time it threw codes and ran badly. This time...................It ran smoothly and NO CODES!!??

I will need to take the car for a run, but today with heavy rain, I decided to chicken out and wait for better weather. Perhaps I did not run it long enough to throw codes, but last time they came on almost immediately. What is baffling is the ECU hard fault has not come back (yet), nor the intake air leak, or the O2 sensor no signal?? The last one ay take more time to sense so may still come back. Even though it is a pain to change, I already have a new one, but that is ok. If the car is reasonably ok with no more unexpected codes, then it will live again! I will update when I get a chance to take it for a run and see how it does.

Neil.

[scot850]

So today I managed to get back to the car with the intention of taking it for a short run to see what if any engine codes returned.

Due to my typically PITA - R, which decided to have a low battery, too low to even boost even having run fine 3 days ago, I could not move the car to get the 02 XC70 out past it to take it for a run. I had to put the R on charge to try to get the battery high enough to to allow my booster to work.

The student, who the car is potentially for, came over to see what progress I'd been able to make and see if he could help in anyway. To kill time, I decided he could go ahead and fit the supposedly good used (and free) power steering reservoir replacing the seriously leaking original. I gave a little supervision but the young guy did all the work draining the header tank ( we measured the amount we removed so we could replace with new fluid), then removing the 2 hoses to the reservoir and swapping in the replacement. Hopefully the original owner of the tank that gave it to me was correct and that it is good. So far, so good!

By then there was enough charge in the battery that using the over-ride function on the booster, the R fired up so it could be moved to the other side of the garage so the XC70 could get out.

We took the car for a careful run around the neighborhood. Immediately on starting the engine the check light came on again. As the engine seemed to be running sweetly, we carried on with the run to see what might come back.

Sure enough 3 codes returned. Failed O2 sensor (no surprise), cam timing signal error again (Aargghh!) and a totally unhelpful error code for a CEM registered fault. I have posted a question on that here:

viewtopic.php?t=105262

The O2 sensor I expected and have a new one for the upstream sensor. I might replace the downstream one as well as I have one.

The cam sensor issue I will do the oil and filter change as suggested, and if that does not work I will have a look if the timing belt was fitted correctly when a repair shop fitted a new one recently. Not concerned, but I will figure this one out eventually.

The last one I can't fix as I have no idea what caused it or how therefore to fix it. Again not too worried.

So based on that and an otherwise successful test run, the student the car is for and I agreed we will continue to compete all the repairs and he will take it on!!

So next up, need to ID and order the shocks and brakes as the largest things to tackle first.

Neil.

[scot850]

Quick update. The suspension (shocks/struts/boots/spring seats) and brakes (rotors/pads) are on order from Rock Auto. Arrival is Friday if they make the promised date. New young owner is not working this weekend so he wants to come over to get started on the repairs, so it sounds like more progress soon!

Neil.

[vtl]

I'm sorry to say that, but most of these engines seem to die of burnt exhaust valve at around this mileage. Valve backlash needs to be checked and adjusted every 100-150k miles, and no one does it, because in this engine it's a very expensive procedure. Your misfires may be coming from a valve on it's way out.

[scot850]

No misfires any more. Only valve issue is a recurring low voltage cam sensor message:

P0016 or (643A) ECM-643A : Cam Position - exhaust: Signal too low

I cannot find any explanation on what this error code actually is. Car starts and runs now smoothly and purrs.

I'm not sure what you mean by cam backlash?

I'm going to do an oil change as it is overdue, but next step will be to drop the oil pan and replace the O-rings.

Over the last 2 days the new owner and I managed to get the front struts and spring seats swapped over, and also both the front and rear rotors and pads. We did not get the rear shocks done yet. Next on the list along with the /O2 sensors and oil and filter change.

Not looking forward to the O2 sensors as the front (upstream) one looks a bear to access. I'll start soaking them both and hope I can get them out ok.

Blacklab247 dropped around and added some good insights and picked up and clarified some suspension issues we will have to pick up on in the future. Rear tires are wearing on the insides so toe out. Some of the bushes are getting toasty.

Found a few issues when working on the brakes. The front RH rotor look badly grooved, but the LH one looked ok and not terribly worn. It was not until re-assembling that I discovered the pad retainer was missing (the owner had stripped that side and did not know there should be one). Caliper brackets are also badly worn and the worst I have seen. Managed to order 2 x Nugeon reman units with brackets and the spring retainer for $30 SCD each plus shipping of about $15 each. We'll swap the brackets and fit the retainer when they get here Tuesday.

Rear brake pads on one side were badly worn. The pad was seized in the caliper. Strangely the new pads were sticking too so I filed them slightly so the now move. We will have to look for brackets for those too as they are also worn badly although not as bad as the fronts.

Also had to replace the front rotor M6 retaining bolts as the threads were damaged, so also re-tapped the threads to clean them.

Best part of the day was working with the enthusiastic new young owner of the car. He is smart and learned quickly which is a joy in itself when teaching someone. Added bonus was BlackLab247 adding his experience and love for his 03 XC70.

Great day!

Neil.

[yanga001]

I'm sorry to say that, but most of these engines seem to die of burnt exhaust valve at around this mileage. Valve backlash needs to be checked and adjusted every 100-150k miles, and no one does it, because in this engine it's a very expensive procedure. Your misfires may be coming from a valve on it's way out.

Is this like a valve adjustment in a honda? I didnt know we could adjust that in these engines?

Are the only options a valve job/new head/engine swap?

[vtl]

I'm sorry to say that, but most of these engines seem to die of burnt exhaust valve at around this mileage. Valve backlash needs to be checked and adjusted every 100-150k miles, and no one does it, because in this engine it's a very expensive procedure. Your misfires may be coming from a valve on it's way out.

Is this like a valve adjustment in a honda? I didnt know we could adjust that in these engines?

Are the only options a valve job/new head/engine swap?

I have never had Honda.

I think only early 5 cylinders (in 850, etc) had hydraulic lifters. Newer ones are all solid tappets, which are good for 220-250k miles and then it gets a burnt exhaust valve. When I was rebuilding my engine that died of burn exhaust valve at ~220k, I had to buy 16 new tappets. 4 old ones I was able to reuse. I had 40 old tappets in total: 20 in my engine, and 20 in the donor. And if you think you should do the same, I have to point that this engine is open block, so it has quite significant bore taper. Can and should throw in new piston rings, but compression and combustion gases blow-by would not be much better.

This engine is pretty balanced for 200k relatively trouble-free miles. Then it's a base for a fancy coffee table with a glass countertop, basically. Or a core for a factory rebuilt engine.

[MoVolvos]

I'm sorry to say that, but most of these engines seem to die of burnt exhaust valve at around this mileage. Valve backlash needs to be checked and adjusted every 100-150k miles, and no one does it, because in this engine it's a very expensive procedure. Your misfires may be coming from a valve on it's way out.

Is this like a valve adjustment in a honda? I didnt know we could adjust that in these engines?

Are the only options a valve job/new head/engine swap?

.
I remember from my short time at Acura a senior tech doing a valve adjustment and the car came back with issues. He said he thought he might be able to get away with it being warm but it must be absolutely stone morning cold.

Never heard of or seen a video on a valve adjustment for Volvo. Wonder if VIDA either mentions or has a tutorial on this?
.

[vtl]

I remember from my short time at Acura a senior tech doing a valve adjustment and the car came back with issues. He said he thought he might be able to get away with it being warm but it must be absolutely stone morning cold.

Never heard of or seen a video on a valve adjustment for Volvo. Wonder if VIDA either mentions or has a tutorial on this?
.

Yeah, I measured my garage cold tappets with home warm micrometer. When I did a second pass I noticed the very first measurements were 0.002" off. Left everything in garage for another overnight, the next two passes went smooth and consistent. I also think the spec numbers are given for 68 F / 20 C temperature. If measured at much colder or warmer, there's and thermal expansion compensation you have to add/subtract.

I think VIDA has the procedure.

[MoVolvos]

I remember from my short time at Acura a senior tech doing a valve adjustment and the car came back with issues. He said he thought he might be able to get away with it being warm but it must be absolutely stone morning cold.

Never heard of or seen a video on a valve adjustment for Volvo. Wonder if VIDA either mentions or has a tutorial on this?
.

Yeah, I measured my garage cold tappets with home warm micrometer. When I did a second pass I noticed the very first measurements were 0.002" off. Left everything in garage for another overnight, the next two passes went smooth and consistent. I also think the spec numbers are given for 68 F / 20 C temperature. If measured at much colder or warmer, there's and thermal expansion compensation you have to add/subtract.

I think VIDA has the procedure.

.
Nice work, however why is this not done or is it like the transmission fluid suppose to be in spec the life of the car? Does VIDA give a mileage or time that this needs to be checked?
.