Diesel power...the D24TIC 940 rolling restoration project

[Laird Scooby]

As you've already run it up to temperature Phil, warm it up again and than park it facing uphill overnight then check the level before any use/starting tomorrow, topping up as needed.
This will help shift any air in the system to the highest point which should be the expansion tank.

[AllHailKingVolvo]

Thanks Jim and Dave!

Car is now bled, and I did a two hour round trip in it this morning. The only problem I've come across is a leaking expansion tank cap-it's a bit grotty and is non-genuine, so have ordered a new green one. I found that after a run the tank had leaked quite a bit, despite not being pressurised or anything alarming like that.

Something I've noticed is that when I rev the car with the cap off, there is a swell of coolant back into the tank from the "exit" hole at the bottom, which then flows out again when the revs stabilise (either at high revs or returning to idle). There are no bubbles or any signs of exhaust gas or oil in the coolant (or vice versa) so I don't think it's a head gasket issue. I figure it's just the water pump spooling up when the car is revved and dumping a wave of coolant back into the rad, causing the level to rise by a centimetre or so.

Unfortunately the hose between the lower coolant union and the cold start device has disintegrated somewhat and is leaking, so the car is benched until tomorrow when a batch of new pipe arrives. I'm changing the heater matrix hoses too as they are looking a bit tired.

I took the instrument binnacle out today and reflowed the solder on all the film PCB joints in the hope of breathing some life back into the dead temperature gauge...sadly I had no luck, so have ordered an aftermarket temp gauge which I will fit tomorrow. I have a feeling the car is running a little hot, so will be interesting to see where we're at.

Other work today has included fitting a couple of missing exhaust clamps, changing the power steering fluid (that's one turkey baster that won't see another Christmas!!) And changing the brake fluid in the MC header tank so it's fresh for when I fire up the Gibson Eezibleed and do a full flush and bleed of clutch and brakes.

Slowly working through the to do list...plenty left to do!

[jpliddy]

hi phil
you are doing well .the pressure in coolant resivour may be answered by the D24.com panel they have a vast knowledge on this engine . i notice my coolant resiovor goes down by about 17 mm when engine is cold then rises to the LIP on the tank when hot i do get a tiny bit of coolant residue around the cap a whitish powder stuff but its tiny . good job to replace hoses when you can .i have been after the 2 hoses of the back of the engine for ages 1 comes round to the drain off tap the other is a short 1 from engine feeding the heater , have you found any for sale as they are unique shapes .please let me know if you do !
regards jim

[AllHailKingVolvo]

Originally Posted by jpliddy

hi phil
you are doing well .the pressure in coolant resivour may be answered by the D24.com panel they have a vast knowledge on this engine . i notice my coolant resiovor goes down by about 17 mm when engine is cold then rises to the LIP on the tank when hot i do get a tiny bit of coolant residue around the cap a whitish powder stuff but its tiny . good job to replace hoses when you can .i have been after the 2 hoses of the back of the engine for ages 1 comes round to the drain off tap the other is a short 1 from engine feeding the heater , have you found any for sale as they are unique shapes .please let me know if you do !
regards jim

Thanks Jim! I'll let you know re the hoses. I replaced my expansion tank cap today with a new green one as in the stickies it mentions that the grey caps can develop hairline cracks in the threads, causing coolant egress...fitted the green one, took the car for a run and the leak appears to have been cured!

The replacement of the hose from the lower union to the bottom of the cold start device was somewhat less straightforward...the company I ordered the spool of hose from sent 10mm ID hose not 12mm, which of course didn't fit! As luck would have it, I had some 19mm ID hose, which the original joining hose fitted inside snugly...so, as a temporary fix I cut off the lower part of the original hose that had disintegrated due to the rocker cover seal oil leak, cut the good remaining section in half, then grafted both ends into a section of the 19mm ID hose, crimping it down with a jubilee clip at each end, making it the equivalent length to the original hose, and refitted it.

Obviously this isn't a long term solution and will be replaced by the correct pipe within the next couple of days, but it was sufficient to get the car running again without dumping coolant everywhere!

Other work today was to cut a section out of the upper radiator hose and fit a joiner section with an M10 thread for a temperature gauge sensor. I bought a gauge kit and fitted the gauge itself under the bonnet in the short term to test it, but the sensor was defective and only worked when whacked with a screwdriver handle! Not ideal...I spoke to the seller and they have agreed to send a replacement sender out to arrive on Sunday, so all will be well.

I will install the gauge in the cabin once it's all working properly, I just wanted to have some method of keeping tabs on engine temps in the short term, having done a bit of work on the cooling system and still being unable to wrestle the dash temp gauge back into life

[AllHailKingVolvo]

Well, today was a winner...I was unsatisfied with accepting defeat over the non-functioning stock temperature gauge, so decided to take the dash out again and see what further sleuthing I could do.

Some more online poking about revealed that the gauges are in fact modular, and that by reflowing the solder on the "master" film PCB I was probably barking up the wrong tree. After a bit of headscratching, I managed to separate the two halves of the instrument binnacle and remove both the temp gauge and the fuel gauge, which also has been a bit unpredictable.

It didn't even take a microscope to see that the temp gauge PCB was riddled with dry joints, and that the solder connection on one of the mounting turrets that also acts as a feed conductor from the film board had totally broken down. Whether this was due to the gauge being closest to the RH heater vent or due to the car living outside for a lengthy period, I'm not sure.

Either way, I spent an hour or so reflowing all of the joints on the boards of both the temp and fuel gauges, made good the failed turret joint on the temp gauge and put it all back together.

To my immense joy, both gauges now work perfectly! And, to my further joy, the car warms up as it should and sits neatly at 12 o'clock with no signs anywhere of running excessively hot at all, the only change being when cruising down a lengthy hill in fifth and entirely off the throttle, when the needle dropped very slightly from midday to around 11:45.

You hear so many horror stories about overheating killing these engines that I think I was jumping at shadows a bit...all fears allayed now!

Next up, some minor brake work, clutch SC bleeding, new gearbox mount and new driveshaft CSB and mount. Should keep me busy for a bit!

[Laird Scooby]

Excellent work and result Phil!

[J liddy]

Yes excellent job phil i have been trying to get my temperature gauge to work for years i swopped the gauge but still the same problem do you have any photos my email is jimliddy1@gmail.com if you coud forward any info be much appreciated
Regards jim

[AllHailKingVolvo]

Originally Posted by J liddy

Yes excellent job phil i have been trying to get my temperature gauge to work for years i swopped the gauge but still the same problem do you have any photos my email is jimliddy1@gmail.com if you coud forward any info be much appreciated
Regards jim

Jim I didn't take any pics of what I did, but I'll collate some online and send you the info on how I sorted it via email. It's a dead simple fix, just a couple of screwdrivers, a decent soldering iron with a pointed bit, some fine solder and a steady hand required!

My new LED dash backlight bulbs arrived today so I was able to reinstall the binnacle and fully reassemble the dash. It looks great with the blue backlighting, much better than with the one surviving original 158 bulb lighting up the top corner of the fuel gauge and nothing else!

[AllHailKingVolvo]

More work today, and lots of it...changed the gearbox mount which had been turned to soup over the last few years by a diesel leak, changed gearbox oil, remade the driveshaft centre support bearing plate mounts (old rubber isolation bushes where the plate meets the body had been turned to soup also by said diesel leak),replaced all the perished rubber exhaust hangers and removed, rebuilt and refitted the clutch MC (nobody mentions that top 13mm nut behind the clutch pedal do they...for good reason &#129315

The driveline work has transformed the car-it's far smoother and the box feels and sounds much better with fresh oil.

I'm not convinced the MC rebuild has entirely sorted the clutch dragging issue, but time will tell. Engagement is still close to the bottom of pedal travel but there is little more I can do without changing the clutch itself, as the car also had a new slave cylinder a year or two ago. I'll drive it and see how it settles in.

I still have to change the driveshaft CSB, but it's not horribly sloppy-probably 2-3cm of play when shoved about. Much less play now the plate isn't flopping around! I'll get to the job soon.

Other than that, there isn't much else to do on the car now mechanically...it needs the calipers stripping and slide pins greasing, I'll check the pads whilst they're out but I think they're in good shape.

What a great ownership experience this car is turning out to be...cosmetic work to come next!

[AllHailKingVolvo]

At last, another day’s work on the car after an enforced layoff due to breaking my right foot and wrist in March...no driving or mechanicing in the interim so was pleased to do some minor bits today!

First job was to fit two new gearbox mount crossmember bushes on the passenger side-the driver’s side bushes were in good condition when I had the crossmember off to fit the new gearbox mount, but the pax side units had, along with the gearbox mount itself, been turned to soup by a diesel leak from the injector pump union block (now solved). I bought a set of four from the Volvo Classic Warehouse and will fit the driver’s side units in due course, but there is currently no need.

Second job was to remove the intermittent remote locking/immobiliser relay and bypass it by making up a jumper cable between terminals 50E and 50F. This was a simple task and the car now starts on the button every time. My petrol 940 has had the same mod done at some point before my ownership, so I’m quite used to life without keyless entry. Much happier than risking being stranded by an uncooperative immobiliser!

Third on the list was to replace the worn original steering wheel with a leather one from a late model 940 which I snaffled from eBay a couple of weeks ago and reconditioned...it was dirty and worn, but cleaned up really nicely and came up like new thanks to a leather restoration kit. Again, a simple task and has really sharpened the appearance of the cockpit nicely.

Once I’ve changed the driveshaft centre support bearing mount, handbrake shoes and diff oil, the car will be pretty much signed off in terms of the mechanical recommissioning. It drives REALLY well and utterly belies it’s 280,000 miles. I have no doubt that it will be good for another 220k at least...I hope to take it over the half a million mark myself!

Once those boxes are ticked, I need to tackle the cosmetic jobs. The interior needs a good valet, the leather treating and nourishing and a few small repairs (door card tops need wrinkle repairs and a couple of the carpet panels and wood trims need refitting), and the bonnet and roof have a significant amount of lacquer damage which needs sorting out...ultimately I’m going to have to pony up to have that done professionally, but at the moment I’m leaving it until last as it’s not an inexpensive job, and will be a lovely finishing touch to the car once everything else is done.