1.9TD (D4192T) electrical(?) problems

[voivoi]

Had a possibility to check the wiring loom in a warm carage today. Looked just fine. There were two heat shrinks. Opened one and it was ok, clear copper. There's a diesel guy in the city nearby. I'll go and ask if he happens to have a suitable advance solenoid. After some more measuring and testing it's definitely sticking.

Originally Posted by V40 SHOOTING BRAKE

https://www.volvoforums.org.uk/showt...ghlight=D4192T

A FRIEND OF MINE OWNED THIS 1998 V40 D4192T FROM NEW.AT 52,000 MILES IT BEGAN TO BLOW WHITE SMOKE ON START UP,LOTS OF NEEDLESS ENGINE WORK DONE,UNTIL A DIESEL SPECIALIST,DIAGNOSED THE PUMP DIAGPHRAGM AT FAULT.

I NOW RUN THE CAR,WITH 66,000 MILES ON IT,NO PROBLEMS SINCE THE PUMP DIAPHRAGM REPLACED.

I'll keep this in mind. Thanks.

[voivoi]

Got a new solenoid from the diesel mech. Not the cheapest out there, but not quite oem price, either. But it helped!

Still something wrong, though. The diesel guy adviced me to put a piece of clear hose to the fuel line to see if there's air. And so it seems. He also said this DPC pump is very sensitive to air.

What part(s) do i need to change in the fuel filter housing to make it air tight? That's the first thing to do I assume?

[Baffler]

Originally Posted by voivoi

Got a new solenoid from the diesel mech. Not the cheapest out there, but not quite oem price, either. But it helped!

Still something wrong, though. The diesel guy adviced me to put a piece of clear hose to the fuel line to see if there's air. And so it seems. He also said this DPC pump is very sensitive to air.

What part(s) do i need to change in the fuel filter housing to make it air tight? That's the first thing to do I assume?

Have you changed the fuel filter in your ownership? If not change it before replacing anything else. The seal may have deteriorated or could be clogged with anti-waxing agent.

Also check the fuel delivery pipes and hose connections are secure on either side of the housing and when you have the filter removed check the pre-heater plate is secured to the housing (think it's a 10mm hex) before fitting the new filter.

If I remember correctly OEM filters on these are manufactured by Purflux.

[voivoi]

I haven't changed it, but according to the service book, it's been done yearly. I'll do that.

[voivoi]

Finally had time to change the filter. I couldn't get it off in the engine bay with my crappy filter wrench, so I took it out with the housing. The pre-heater bolt (8 mm hex ) seemed a little loose maybe. Anyway, I took it all apart and cleaned it. I also installed, temporarily, a clear fuel hose from the housing to the injection pump. The original hose has seen better days, but I'm not sure if it really leaked. Result: no air. Hooray!

But. I've had some headaches with the engine temp lately. First it started to get hot, just below red. I took the thermostat out and tested it and it seemed faulty so I put a new one in. I also tested it before installing to be sure. But now the temp meter doesn't rise high enough. I got the fan to turn on so it did warm up, but that was at stand still and the meter still read low. Some questions:

There are two sensors at the thermostat housing. One for the temp meter and the other for the over temp warning light, am I right?

Is the thermostat supposed to be installed with a single o-ring?

Is there an idiot proof method to bleed the cooling system?

More for curiosity; does the engine use temp info?

[voivoi]

And what about that nipple in the original thermostat? What's it there for and should the new thermostat have it?

[Baffler]

Originally Posted by voivoi

Finally had time to change the filter. I couldn't get it off in the engine bay with my crappy filter wrench, so I took it out with the housing. The pre-heater bolt (8 mm hex ) seemed a little loose maybe. Anyway, I took it all apart and cleaned it. I also installed, temporarily, a clear fuel hose from the housing to the injection pump. The original hose has seen better days, but I'm not sure if it really leaked. Result: no air. Hooray!

Good for you! Glad you're getting it sorted.

But. I've had some headaches with the engine temp lately. First it started to get hot, just below red. I took the thermostat out and tested it and it seemed faulty so I put a new one in. I also tested it before installing to be sure. But now the temp meter doesn't rise high enough. I got the fan to turn on so it did warm up, but that was at stand still and the meter still read low. Some questions:

There are two sensors at the thermostat housing. One for the temp meter and the other for the over temp warning light, am I right?

If I'm not mistaken one sends a signal to the instrument panel gauge and the other feeds info to the ECU.

Is the thermostat supposed to be installed with a single o-ring?

Yes, there should be a metal plate with a raised lip, on the underside of the cap, to compress the seal against the thermostat which in turn seals against the housing. Apply a little silicone grease or petroleum jelly to the seal to ease assembly.

Is there an idiot proof method to bleed the cooling system?

It should self bleed but air can get trapped in that lower radiator hose. At first I would remove the expansion cap, bring the engine close to operating temp and massage the lower hose to persuade any air to the top.

There should be a single brass bleed screw on the highest point of the stat housing and there is also a plastic bleed screw on the inlet hose feeding the heater matrix core but these are usually snapped off due to heat damage.

Keep a few litres of coolant/water mix with you in the car to top up as necessary.

And what about that nipple in the original thermostat? What's it there for and should the new thermostat have it?

That bypass nipple allows a small amount of coolant to move freely around the water jacket, whilst the thermostat is in the closed position, preventing an unnecessary build up of pressure in the system. Yes, ideally you need one as not having one makes bleeding so much more difficult.

[voivoi]

Originally Posted by Baffler

Good for you! Glad you're getting it sorted.

Oh well, that joy was somewhat premature. Still gets air in the fuel line. Not as much as before and not all the time like before. Should've changed the piece of hose from the filter to metal piping, too, while changing the filter. That would tell a lot at this point.

Originally Posted by Baffler

If I'm not mistaken one sends a signal to the instrument panel gauge and the other feeds info to the ECU.

Yeah, that's what the service manual says. I was reading some web shop descriptions for the sensors and they got me distracted.

Originally Posted by Baffler

Yes, there should be a metal plate with a raised lip, on the underside of the cap, to compress the seal against the thermostat which in turn seals against the housing. Apply a little silicone grease or petroleum jelly to the seal to ease assembly.

Mine's not like what you describe, no metal plate. I think the cap itself has the lip you mean. Anyway, took it apart again and I'm pretty sure it seals ok.

Originally Posted by Baffler

It should self bleed but air can get trapped in that lower radiator hose. At first I would remove the expansion cap, bring the engine close to operating temp and massage the lower hose to persuade any air to the top.

There should be a single brass bleed screw on the highest point of the stat housing and there is also a plastic bleed screw on the inlet hose feeding the heater matrix core but these are usually snapped off due to heat damage.

Keep a few litres of coolant/water mix with you in the car to top up as necessary.

That bypass nipple allows a small amount of coolant to move freely around the water jacket, whilst the thermostat is in the closed position, preventing an unnecessary build up of pressure in the system. Yes, ideally you need one as not having one makes bleeding so much more difficult.

It seems that some like to drill holes in the thermostat plate. I considered doing that, but eventually didn't. Used massaging instead. The brass screw is so hard to reach, with my tools at least, I think it's pretty much useless.

Also hooked up an external themometer on the upper hose with some insulation over it so it should be accurate enough. When it showed about operating temperature, the dash gauge was still significantly lower. So maybe it's electrical then. Hopefully the sensor.

[Baffler]

Oh well, that joy was somewhat premature. Still gets air in the fuel line. Not as much as before and not all the time like before. Should've changed the piece of hose from the filter to metal piping, too, while changing the filter. That would tell a lot at this point.

Persevere, you'll get to the bottom of it!

Mine's not like what you describe, no metal plate. I think the cap itself has the lip you mean. Anyway, took it apart again and I'm pretty sure it seals ok.

I'm confusing the earlier type housing/cap with that of the later F9Q/D4192T3/4 housing/cap.

It seems that some like to drill holes in the thermostat plate. I considered doing that, but eventually didn't. Used massaging instead. The brass screw is so hard to reach, with my tools at least, I think it's pretty much useless.

Drill the hole...release the pressure...or buy the type with the bypass nipple. MotoRad are the manufacturer if my mushroom serves me correctly.

Also hooked up an external themometer on the upper hose with some insulation over it so it should be accurate enough. When it showed about operating temperature, the dash gauge was still significantly lower. So maybe it's electrical then. Hopefully the sensor.

You may still have an air lock or silt blockage in there somewhere but that usually causes the temp gauge to fluctuate wildly. Have you flushed out the whole system, including the heater matrix, with a low pressure supply (eg: garden hose)?

Also...was it reaching 3 o'clock on the temp gauge prior to replacing the original thermostat? If not you may be loosing system pressure somewhere. The expansion tank cap has a built-in release valve which do fail on occasion and the expansion tank itself, where it tapers down behind the strut tower, are known to develop hairline cracks. One member reported a few years back on discovery of a pin hole on the underside of the metal pipe which runs along the right chassis leg.

[voivoi]

Originally Posted by Baffler

You may still have an air lock or silt blockage in there somewhere but that usually causes the temp gauge to fluctuate wildly. Have you flushed out the whole system, including the heater matrix, with a low pressure supply (eg: garden hose)?

Also...was it reaching 3 o'clock on the temp gauge prior to replacing the original thermostat? If not you may be loosing system pressure somewhere. The expansion tank cap has a built-in release valve which do fail on occasion and the expansion tank itself, where it tapers down behind the strut tower, are known to develop hairline cracks. One member reported a few years back on discovery of a pin hole on the underside of the metal pipe which runs along the right chassis leg.

A year ago when I got the car, the temp gauge didn't reach 3 o'clock in normal driving. But it had the blown head gasket and the thermostat was also toast, propably due to oil in coolant (it had a rubber seal on the valve itself). With a new head gasket and thermostat (without the nipple), the gauge reached 3 o'clock and worked perfectly until a couple weeks back, when it after driving two hours started to slowly rise and reached just below red. After replacing that thermostat, it has shown max 4 o'clock or so. But no wild fluctuation at any point.

After replacing the head gasket I flushed the system with a chemical for that. I think it was made by Kent, but anyway it smelled nasty and effective and surely got a lot of goo out.

Anyway, went to a local parts store and ordered a new sensor. We'll see what that does.