2013 TDCi Engine Temperature Varying

AlCan · 28-09-2024, 09:56 AM

Hi Guys,

Just back from the cold NZ south, and have really noticed the "dreaded" overcooling problem on my 2013 TDCi. This problem is discussed in various places around the net, mainly relating to MB / DW10B engines, but doesn't seem to appear here. And I can't find the answers I need, anywhere. There is another thread here about engine temps, but it doesn't mention the oil thermostat.

Basically (as typical) the engine is slow to heat up, especially in cold weather, then varies all over the place, below normal temp.

In cool weather, the temperature struggles to get over 70 degrees - i.e the first line after the 60° line. If the engine is working hard, it will get up to normal temperature, just shy of the middle, vertical line, but as soon as it's at reduced load, the temperature drops back again. I know this is normal during a long downhill but not for ordinary highway driving. This doesn't happen on the 2011 TDCi, and sounds exactly like the oil cooler thermostat problem discussed on Talkford and elsewhere.

Do the DW10C engines even have an oil thermostat?

The 2011 is also a DW10C but has hydraulic Power Steering, whereas the 2013 is electric. Can't imagine that has anything to do with it, but as above, the 2011 engine temperature remains almost rock steady once it's warmed up. So, there's something different.

I've searched the net for oil thermostats and only found them for engines up to 2008. P/N 1128018. Looks just like a baby, old-style radiator thermostat housing, but skinnier. Can't find anything for later models. The DW10B oil thermostat appears to live on the front(?) centre of the engine, about where the 10C EGR valve is, but I can't see much else in that area.

Can anyone throw any light on this, please?

AlCan · 28-09-2024, 07:25 PM

I'm hoping someone has a Parts Diagram and can put this question to bed, but in the meantime, I've done a bit more research and some thinking about this.

The Engine Oil Cooler is in fact an Oil<->Water Heat Exchanger, located below the Engine Oil Filter Housing on the lower front of the engine. The Housing seems to bolt to the Heat Exchanger or vice versa, and it's very compact and hard to see what's going on. There seems to be a (coolant?) pipe coming out of the block below the intake manifold and heading down, which probably feeds the Heat Exchanger but there was no visibility on the black and grimy wrecker's yard engine I looked at.

Anyway, it's rare that things are improved by removing parts but this might be just such a case. If the coolant feed to the Heat Exchanger is continuous (no separate thermostat as on 10B engines) and comes hot from the engine BEFORE (i.e upstream, inner side of, i.e. the water pump output side of) the Main Coolant Thermostat, then it could serve a dual function.

When the oil is cold, it could actually heat the oil to near Engine Coolant Temperature (about 80°C), which is almost ideal, while when the oil is over 80°, it would pass heat to the coolant, bringing its temperature down closer to 80°. All temperature control would thus be achieved by the single Coolant Thermostat in its housing at the flywheel end of the head. This would also help explain why these engines seem to take so long to warm up, as they also have to heat up 5.5 litres of oil before the engine will get to thermostat opening temperature.

I don't know if this is how it works but it makes sense to me. Could even call it an elegant design...

If so, would mean the problem must be with the Coolant Thermostat itself, which must be not closing fully or has a faulty seal so that coolant is bypassing it. It looks like a bit of a job to change, but not that bad. Probably much easier than pulling the Oil Filter/Heat Exchanger out - if there's even a thermostat there somewhere.

So, my next question is, what coolant is recommended here, please?

**aussiblue** · 28-09-2024, 09:06 PM

This? https://www.youtube.com/watch?v=iZTadyzsrxE

Peter B - CV8 · 29-09-2024, 07:16 AM

All those symptoms indicate a coolant thermostat problem to me ie stuck open.

AlCan · 29-09-2024, 08:36 AM

Thanks too, Peter B,

I totally agree. It sounds exactly like a bypassing thermostat - I even went and bought a new thermostat assembly. Just haven't had the time / opportunity to fit it yet.

But then I did more reading, and am learning that with these cars, things are too often not what they seem.

(For example, even a mechanic said that the blown injector seal was due to a rocker cover gasket leak, dripping oil onto the manifold. I couldn't see / believe that, but it still took me 5,000km+ to figure out what it really was.)

From the net, it sounds like the oil thermostat can also be a hidden problem that swapping the coolant stat won't fix, so I wanted to try and see which it was first. But since there (now) doesn't appear to be an oil stat in the 10C engine, it can't be that. However, with the addition of the EGR video, I still have two possibilities.

Call me lazy, but I prefer to eliminate the possible easy fixes before I tackle the less easy! TBH, this EGR valve possibility is a nice little spanner in the works.

I still agree with you that the coolant stat is more likely, but if it's the EGR and a spray can will fix it... I'll certainly let you know!

AlCan · 29-09-2024, 08:15 AM

Thanks Blue! Who would have guessed that? Still makes no sense to me, but I will definitely check it out / try it and let everyone know.

If it works, then I'll have to figure out why... I believe the EGR valve is open at idle (with the engine cover off you can see that the EGR pushrod position has moved), but I don't understand why it would cause the engine to cool that much if it's stuck / dirty / not opening or whatever the problem is.

Seems to me, the EGR valve is the car owner's worst enemy, the carmaker's friend and the mechanics nemesis! So many things to so many people and the cause of so many completely weird problems.

I still don't understand why Exhaust Gas Recirculation is actually beneficial. It reduces the amount of available Oxygen which supposedly reduces the amount of NOx created, but surely, it also increases the amount of incomplete combustion leading to (even more) soot and other partially burnt fuel products, which I imagine are worse for health than NOx. We need Nitrous Oxide in our bloodstream to dilate blood vessels and control Blood Pressure... Can anyone tell me why EGR is good?

I know the stink (Cooked meat in the Alan Howat video) from partially burnt fuel when there's a blown copper washer injector seal - which was bad enough to make a couple of people I know feel sick and refuse to ride in the ('11) car, but that's all sorted now. Though, a component of that unburnt fuel still lingers in the car - can smell it when you first open the door after sitting awhile. The '13 has it too, though that must have all happened before I bought it.

Anyway, the car is still down south as I flew back this trip and won't get back to it until mid-October. Will update then. Thanks again.

NZ XR6 · 02-10-2024, 02:41 AM

My MB does something similar, it's always taken a while to warm up and the temperature drops on a long downhill. It's been like this for a long time, but never goes above the halfway mark on the temp gauge. If it stays low or overheats, I'll investigate further.

Interesting to know it has a heat exchanger to cool the oil, which may partly explain why it has always been slow to warm up.

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AlCan · 02-10-2024, 05:44 AM

Quote:

Originally Posted by NZ XR6

My MB does something similar, it's always taken a while to warm up and the temperature drops on a long downhill. It's been like this for a long time, but never goes above the halfway mark on the temp gauge. If it stays low or overheats, I'll investigate further.Interesting to know it has a heat exchanger to cool the oil, which may partly explain why it has always been slow to warm up.

Hi Fellow Kiwi,

Your one sounds like it's normal, same as my 2011 MC. I agree, the HE probably does / must increase warmup time, but running warm oil thereafter must improve overall fuel economy (and engine life?) I'm very impressed with these engines and they have really changed my opinion of French engineers. (Pity about the P/S transmissions though! Are they US-designed?)

The 2013 has this varying low temperature problem, and I can't wait to see if the EGR has something to do with it - but it's down in the SI.

Regarding the Heat Exchanger, does the MB have a DW10B engine? I don't know very much about those, and I'm not sure if it has an Oil Cooler / Heat Exchanger (I think they maybe all do), but they might also have that Oil Temp Thermostat. Or they stopped using those after 2008? Don't know, but you can find them all over the place, just Google Images for 'Mondeo 1128018'. The MC/DW10C engine also seems to have a small (oil?) cooler located on the underside of the driver's (Ok, right-)side floorpan but I haven't done any investigation of that as yet.

These cars are nothing if not interesting!

NZ XR6 · 02-10-2024, 09:55 AM

Quote:

Originally Posted by AlCan

Hi Fellow Kiwi,

Your one sounds like it's normal, same as my 2011 MC. I agree, the HE probably does / must increase warmup time, but running warm oil thereafter must improve overall fuel economy (and engine life?) I'm very impressed with these engines and they have really changed my opinion of French engineers. (Pity about the P/S transmissions though! Are they US-designed?)

The 2013 has this varying low temperature problem, and I can't wait to see if the EGR has something to do with it - but it's down in the SI.

Regarding the Heat Exchanger, does the MB have a DW10B engine? I don't know very much about those, and I'm not sure if it has an Oil Cooler / Heat Exchanger (I think they maybe all do), but they might also have that Oil Temp Thermostat. Or they stopped using those after 2008? Don't know, but you can find them all over the place, just Google Images for 'Mondeo 1128018'. The MC/DW10C engine also seems to have a small (oil?) cooler located on the underside of the driver's (Ok, right-)side floorpan but I haven't done any investigation of that as yet.

These cars are nothing if not interesting!

When it was new, the temperature stayed constant once it finally warmed up, which could take 10 minutes on a cold morning.

I'm not sure about the engine type in mine. Ford changed to a Euro 5 engine late 2010, and I understand there are some MB's with the later engine and Powershift box. Very pleased I didn't get one of those!

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AlCan · 02-10-2024, 11:04 AM

Which g/box do you have?

The DW10C engine has the oil filler in the near left corner of the engine cover (viewed from the radiator), and the dipstick ~100mm away at about 1:30 from there. And the soft rubbery cover over the injectors.

I'm guessing that the completely stable temp when new was because it was still running in, so more frictional heating. On long downhills, fuel injection shuts off completely (per the Economy readout in the Amber digital display), and there's not much else to generate heat. More noticeable in cold conditions.

NZ XR6 · 05-10-2024, 04:53 AM

Quote:

Originally Posted by AlCan

Which g/box do you have?

The DW10C engine has the oil filler in the near left corner of the engine cover (viewed from the radiator), and the dipstick ~100mm away at about 1:30 from there. And the soft rubbery cover over the injectors.

I'm guessing that the completely stable temp when new was because it was still running in, so more frictional heating. On long downhills, fuel injection shuts off completely (per the Economy readout in the Amber digital display), and there's not much else to generate heat. More noticeable in cold conditions.

It's the 6 speed auto. From your description, the car has the DW10C. It goes well and gets around 6 l/100 km on long trips. But with the current RUC and diesel pricing, it's probably more expensive to run than a petrol car.

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AlCan · 02-10-2024, 06:28 AM

FWIW...

The MPS6/DCT Power Shift Transmissions were made by Getrag of Germany.

Getrag had three JV companies, one with Ford, also in Germany (Cologne).

In 2015, Getrag was acquired by the US company Magna Powertrain. Not sure what then became of the Ford-Getrag JV.

Peter B - CV8 · 03-10-2024, 07:17 AM

A faulty coolant thermostat(ie stuck open) will result in a longer engine warmup & running too cool when cruising, especially on downhill coasting.

AlCan · 03-10-2024, 09:43 AM

Hi Peter,

Yes, got it, thanks!

Please forgive me - I'm not ignoring your good advice! I was a 'problem' child and apparently still am!

I agree completely that a faulty thermostat is very likely and behaves exactly as described, to the point that I already bought one. Just haven't installed it yet...

Now learning that these cars are slippery critters that love to make mischief for us hapless owners. (I have another thread to start soonish which may show that very clearly.)

As aussiblue has tossed in another possibility (EGR valve issue), I want to check that out first since it's a 2 minute job. If I have an EGR valve that's currently at the rumoured "sweet spot", I think it's worth investigating. It makes no obvious sense and may be a complete wild goose chase but I'm up for it.

Just can't get my hands on the car for another couple of weeks.

Peter B - CV8 · 04-10-2024, 07:01 AM

No worries mate - all good :-)
Hope the fix is a simple & cheap one. Keep us posted.

AlCan · 11-10-2024, 12:25 PM

Update:This morning, with the EGR vacuum line disconnected and plugged, I monitored Engine Temps through warmup. The ambient temp was a moderate 8.0°C at the start. The Heating/Air Cond system was completely Off.Initially, from cold and driving in a 50km/h suburban area without any traffic lights or lengthy stops, the engine temp took 5 minutes to cross the 60° line, 6 minutes to pass 70° and about 7 minutes to reach "Normal" at about 78-79°C.This is the first time I've seriously studied the warmup behaviour, and I noticed the same thing as reported elsewhere (not sure where, can't find it now), namely: As soon as the engine reached normal operating temperature and the thermostat opened, the coolant temp declined again. It dropped back to about 75° on the gauge, by which time I was into an 80k zone and the engine was working a bit harder. My 2011 wagon doesn't do this, but holds a steady normal (78-79°C on gauge) coolant temperature except during long downhill runs, or hard hill climbs.When I got to the 100km/h area and a slight uphill gradient, the temp sat at about 76. When stopped to turn around, ambient was 9.0°. Temp went back to about 79 while stopped, but on the way back, with a slight downhill, it was mostly at 75.I know it goes lower when air temps are around zero, but summer's on its way. From memory, it drops to around 65 on very cold days.Looks like I just have a lazy, el cheapo thermostat. Funny that it reaches normal before opening, but rarely goes back there.I guess simply disconnecting the EGR doesn't prove it's not involved somehow (it may be stuck or not opening, or closing, fully), but the fact that the behaviour seems very similar to how it was before suggests to me that the EGR valve is probably a red herring here. The car drove just like it usually does, including the combustion crackle this engine makes at a certain RPM under partial load. Maybe that YT guy sells EGR Cleaner! I'm not gonna bother buying any.I know the temps I report here don't sound too bad, but chronic low temperature running causes increased wear, especially in petrol engines. I presume more bore glazing and carbon deposits in diesels?Looks like there are batches of dodgy thermostats out there and it's a pain that the thermostat itself is not removable from its housing. Consumer Capitalism at its best! For now, I think I'll enjoy the coming summer and not worry about it.Unless someone can convince me there's a separate oil cooler thermostat that may be relevant...

AlCan · 11-10-2024, 12:32 PM

Update:This morning, with the EGR vacuum line disconnected and plugged, I monitored Engine Temps through warmup. The ambient temp was a moderate 8.0°C at the start. The Heating/Air Cond system was completely Off.Initially, from cold and driving in a 50km/h suburban area without any traffic lights or lengthy stops, the engine temp took 5 minutes to cross the 60° line, 6 minutes to pass 70° and about 7 minutes to reach "Normal" at about 78-79°C.This is the first time I've seriously studied the warmup behaviour, and I noticed the same thing as reported elsewhere (not sure where, can't find it now), namely: As soon as the engine reached normal operating temperature and the thermostat opened, the coolant temp declined again. It dropped back to about 75° on the gauge, by which time I was into an 80k zone and the engine was working a bit harder. My 2011 wagon doesn't do this, but holds a steady normal (78-79°C on gauge) coolant temperature except during long downhill runs, or hard hill climbs.When I got to the 100km/h area and a slight uphill gradient, the temp sat at about 76. When stopped to turn around, ambient was 9.0°. Temp went back to about 79 while stopped, but on the way back, with a slight downhill, it was mostly at 75.I know it goes lower when air temps are around zero, but summer's on its way. From memory, it drops to around 65 on very cold days.Looks like I just have a lazy, el cheapo thermostat. Funny that it reaches normal before opening, but rarely goes back there.I guess simply disconnecting the EGR doesn't prove it's not involved somehow (it may be stuck or not opening, or closing, fully), but the fact that the behaviour seems very similar to how it was before suggests to me that the EGR valve is probably a red herring here. The car drove just like it usually does, including the combustion crackle this engine makes at a certain RPM under partial load. Maybe that YT guy sells EGR Cleaner! I'm not gonna bother buying any.I know the temps I report here don't sound too bad, but chronic low temperature running causes increased wear, especially in petrol engines. I presume more bore glazing and carbon deposits in diesels?Looks like there are batches of dodgy thermostats out there and it's a pain that the thermostat itself is not removable from its housing. Consumer Capitalism at its best! For now, I think I'll enjoy the coming summer and not worry about it.Unless someone can convince me there's a separate oil cooler thermostat that may be relevant...

AlanM · 18-10-2024, 05:16 PM

Have you checked that your radiator shutters are working properly? At those kinds of ambient temperatures they should be shut.

The purpose of the EGR valve is to reduce combustion temperatures and thus NOx emissions.

They do cause plenty of trouble, the recycled soot combines with the oil vapour from the PCV system to produce a sticky black sludge that coats the inlet manifold downstream of the throttle body. This can get so thick it partially blocks the inlet manifold, builds up on inlet valves and causes power loss.

On the bright side, if the EGR system somehow accidentally got blocked by a random bit of metal, the PCM doesn't notice at all. You get no codes or check engine light. And your fuel economy improves a little too.

AlCan · 18-10-2024, 06:15 PM

Quote:

Originally Posted by AlanM

Have you checked that your radiator shutters are working properly? At those kinds of ambient temperatures they should be shut.The purpose of the EGR valve is to reduce combustion temperatures and thus NOx emissions. They do cause plenty of trouble, the recycled soot combines with the oil vapour from the PCV system to produce a sticky black sludge that coats the inlet manifold downstream of the throttle body. This can get so thick it partially blocks the inlet manifold, builds up on inlet valves and causes power loss.On the bright side, if the EGR system somehow accidentally got blocked by a random bit of metal, the PCM doesn't notice at all. You get no codes or check engine light. And your fuel economy improves a little too.

AHA!!! Didn't even know it had shutters... Even in NZ/Aust? That would be a nice feature. These really are good cars. Will have a close look! Many thanks.

Thanks, Yeah, I'm learning about EGR valves. I see you can even buy a fancy laser-cut stainless plate off eBay or somewhere. Video even shows you how it "falls" into place relatively easily.

My question there is, if the valve is closing / closed, is there any advantage to this little mishap? How about another: if the vacuum line fell off the EGR servo and sucked up a short piece of 5mm dia rod, would that be a good equivalent? Somehow, I know that doesn't trigger any errors either, but is there a downside here?

I really don't like the sound of a gunged up intake manifold. If that's what it's sucking, what happens to the engine oil, and the bore lubrication / piston wear? Sounds like robbing Peter now to pay Paul later.

AlanM · 18-10-2024, 07:08 PM

The shutters are pretty easy to see, just look in the lower grille.

Yeah, all that recycled soot isn't good for oil life.

But they do this stuff to pass euro emissions rules. It was pretty much they did this or they stopped selling diesels.

If you can keep the actual valve shut that would work fine. As long as it actually is shut and sealing properly. A lot of the EGR based problems are caused by the valve not shutting when it should.

AlCan · 19-10-2024, 08:32 AM

Quote:

Originally Posted by AlanM

The shutters are pretty easy to see, just look in the lower grille. Yeah, all that recycled soot isn't good for oil life.But they do this stuff to pass euro emissions rules. It was pretty much they did this or they stopped selling diesels. If you can keep the actual valve shut that would work fine. As long as it actually is shut and sealing properly. A lot of the EGR based problems are caused by the valve not shutting when it should.

Thanks for these points! Yes, I guess they were forced to make them comply... Lucky we don't have those rules and nobody checks! And that it's so easy work around, and is, by and large, actually an improvement!

Checked out the Shutters just now.

Not sure if good or bad...

The ('13's) shutters are intact and apparently operating as expected (without a test drive). They are Open when Ignition is Off. They close as soon as Ignition ON, (don't even need to start engine as suggested in Badger video), and Open again as soon as ignition Off. I guess that's the buzzing noise at Switch On/Off. (No mooing as didn't start.) I guess this is all that's really needed to confirm they are good? Anyone had issues where they don't operate correctly between these extremes?

It's looking more and more like the thermostat itself. Not sure which is worse to fix. Broken Shutters look like a bumper off job, but maybe not as bad as the thermostat change?

OTOH, the 2012 (Clutch Slipper)'s Shutters are multi-broken. One (LHS) is missing, the other two that side spin freely. The Lower RHS one spins freely and the other two don't move at all. Definitely a pull apart job.

However, that car doesn't seem to suffer overcooling to the extent that the '13 does. I'm guessing has a good thermostat. Good to be able to compare two, where they are the same.