The real cause of injector rattle?

[JTaylor2005]

I don't unfortunately I need to get an old xp laptop sorted and get peugeot planet tbf. Wanna start looking at this stuff more.

[Paul_13]

What worries me is that I find the temp gauge dreadfully inaccurate. It may be showing under 80'c but on pp2k is running a lot higher

[JTaylor2005]

Working on the basis that the gauge goes up to 120c before getting into the red zone I am not that worried tbf.

As for the difference between the sensor and the gauge I found that changing my gauge and cleaning up the mating faces raised and stabilised the reading on the gauge. Which I can only asume has made it read closer to the actual value.

[Piggy]

100degrees and you've got engine frying issues.

120 and she'll be goosed

[JTaylor2005]

So what does the gauge go up to then before the red zone? 70 has a line. Then 80c. 90c is at the top line and then two more before the line before the red zone. 100, 110, 120 final line? Or does it not make sense like that?

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So far the highest it has gone on the gauge is 95ish c. That was after crawling up a hill side tiny road at 3000rpm in 2nd haha. Normal running it sits just under 90 on the gauge.

[MY95]

100 degrees for engine frying sounds a bit scary, but also a bit low for frying an engine, aren't the high speed fans only supposed to come on around the 100 mark? 103 im sure ive heard somewhere? id go by Peugeots red line over anything else, as if these are meant to run at 88, 12 degrees out isn't massively far out, and its not exactly a DV6.
Also had mine to 95 like JT, but that was sitting still in traffic/stop start at 25 degree heat on the motorway aha.
Although happy that mine runs between 73 and 83 though aha.

[JTaylor2005]

Have to say even after ragging it up that hill which was a hell of a pull the fans didn't kick in. I know they will kick in when needed as I have removed the sensor cable before and they have come on and the sensor is brand new so they do work.

The thing is these cars are designed to work anywhere from the north of Canada right up to the high temps of places like Saudi Arabia. The reason the gauges go way up above 90c before the red section is because they often run hotter in other countries under stressful conditions.

[Piggy]

If both of yours are HDI then I am honestly amazed, and a bit concerned, that they are getting that hot. Tugging a 550kg trailer up a long hill in summer won't even get Mrs Piggy stg1 206 up to 90!
Stats open at 83 iirc and fans around 93-95 afaik. Fans coming in at 103 be way too late

[welshpug]

coolant in the pressurised system will not boil till over 130 degrees.

[Piggy]

Just because it doesn't boil doesnt mean it won't cause engine killing issues. 100degrees is 100 degrees, bubbling or not.

[Toms306]

100c coolant temp shouldn't kill the engine, full speed fans in the HDi don't come on until 98c! The '6 full speed fans come on after 100. You should be good up to about 120c at least without any issues.

[JTaylor2005]

The thing is. I know the fans work on my car. I have just never got it hot enough to get them to come on yet. Modern cars they are on and off all the time. I haven't even had mine on even in traffic haha. I know they work as I have unplugged the sensor before and they came on. Also a stop light lit on the dash because it thought it was too hot. I'm not even close to that even with the car board in at the moment.

[Ruan]

Bring even a stock XUD9 on full power with the coolant temperature past 100*C and I'll put money on the gasket popping.

You *NEED* to get some sort of accurate gauge in there, not just relying on the crappy in dash one, they're well known to talk total bollocks.

Also, WRT the preinjection rattle when the engine is hotter... There's no correction of the preinjection quantity (or angle...) past 80*C from what I've seen - so any changes are purely physical.

Look at the calibration of corrections vs coolant temperature made by the ECU, you'll find that almost ALL of the corrections stop and they run at their normal base values at 80*C - that's because these engines were designed to run at that temperature.

[Toms306]

The thing is. I know the fans work on my car. I have just never got it hot enough to get them to come on yet. Modern cars they are on and off all the time. I haven't even had mine on even in traffic haha. I know they work as I have unplugged the sensor before and they came on. Also a stop light lit on the dash because it thought it was too hot. I'm not even close to that even with the car board in at the moment.

The thing is. I know the fans work on my car. I have just never got it hot enough to get them to come on yet. Modern cars they are on and off all the time. I haven't even had mine on even in traffic haha. I know they work as I have unplugged the sensor before and they came on. Also a stop light lit on the dash because it thought it was too hot. I'm not even close to that even with the car board in at the moment.

That's full speed fans though, the low speed may not work?

That said, I can't remember the last time fans came on in any HDi I've owned, they do run pretty cool. Even thrashing or idling in traffic. I usually check they work through PP just to make sure!

Fans are on and off all the time in modern cars to keep at an optimum temp for emissions regs iirc, back in ~2000 they weren't so bothered about that so fans are just to stop engine damage in older stuff. I think the HDi slow speed fan is 92c, which is just under 90 on the gauge usually lol.

Bring even a stock XUD9 on full power with the coolant temperature past 100*C and I'll put money on the gasket popping.

It's an HDi though? You can drive them with no water in and they're still fine (from experience) lol. The head won't get anywhere near as hot an IDI one so it'll be able to take a higher coolant temp surely?

[Ruan]

I agree, but even so, I don't see why you'd purposefully run an engine at a higher temperature than it was ever designed to run at!?

My point was merely to show that an XUD9TE gauge displays the same old "red" section at 120*C or so, which if it manages to get there, the head gasket is history! Don't rely on the gauge meaning it's safe to do that.

PSA didn't just go "nahm8 gonna run this bitch at 82*c for teh lulz cuz we like cold engines and make it use more fuel"... If the outside temperature is less than 50*C or so, they're designed that they SHOULD be able to maintain their normal coolant temperature of around 83*C. I've monitored the engine temperature in the Volvo, still runs at 82-83*C... Almost all Diesels I'm aware of will run at 82-83*C, the gauge may not say so, but they should run in that region. I would also put money on an increase in coolant temperature gaining any improvements in economy.

Added to the fact even within the ECU, everything is aiming for between 80-85*C operating temperature, any increases past there and you're likely to find you're running into corrective action to *reduce* the temperature by the ECU.

Also, putting cardboard over your radiator is just an indication that your thermostat is shagged. Doing that should only have the net effect that you've reduced the radiator area and make no difference to operating temperature - that's why you have a thermostat!!! Go buy a genuine PSA one and it will run at the correct temperature.

[Piggy]

Fyi... My gauge reads 70 when my aftermarket reads 80

[Toms306]

Ah, fair point! I wouldn't purposely run one at that, but I also wouldn't be worried if it hit that in traffic before the fans came on, I certainly wouldn't be thrashing it about over 100!

Seems odd the gauge red line isn't set for safety though, I would've assumed it was fine until the red, as with RPM.

Coolant temp in the Focus also sits at a solid 83 while driving after hitting 85 and the stat opening. I've never seen it hit 90 on diags even in traffic, fans come on about 88c.

[Ruan]

Ah, fair point!  I wouldn't purposely run one at that, but I also wouldn't be worried if it hit that in traffic before the fans came on, I certainly wouldn't be thrashing it about over 100!

Seems odd the gauge red line isn't set for safety though, I would've assumed it was fine until the red, as with RPM.

Coolant temp in the Focus also sits at a solid 83 while driving after hitting 85 and the stat opening.  I've never seen it hit 90 on diags even in traffic, fans come on about 88c.

Presactly - just use the correct thermostat and it'll run at the correct temperature.

I've never seen motorfactor ones be any good, they're always shite and usually jam after 30 seconds or just don't work from day one. Get a genuine PSA one.



Look how nice I am. Notice what it says on it, 83 Degrees, no other superseded parts, it's always been an 83*C thermostat.

[JTaylor2005]

Just because a thermostat opens at 83 doesn't mean that's the temp it should run at. 83 is when it first starts cracking open not what it's target temperature is. The target is more than likely higher than that. Usually around 88-90 on a lot of cars.

[Toms306]

90 is more petrol temp tbh, the TU thermostat is set at 89c. Diesels do run cooler.

[JTaylor2005]

Ahhhh touche haha

[toseland]

the fact that the thermostat is designed to open at 83 and will be fully open within 8 degrees C of this is negligible..

If the thermostat just flew open fully at the optimum temperature the temperature of the coolant would drop dramatically and reduce the engine well past the optimum of 83degrees.

It is an antagonistic system, more temperature results in further opening which results in cooling via the radiator which results in closing of the thermostat and raising of the temperature and this will be tuned to a specific level, say 83degrees and hence as an average (it will always fluctuate within a small range)

I would hazard a guess that under normal operating conditions on a 20degreeC day the thermostat and cooling fans working well the water being pumped into the engine will be somewhere around 83degreesC or very close. The low heat output of this engine is demonstrated by the need for the pre-heater and the fact that it takes a while for the heater matrix to get hot. (although this isn't connected to the radiator system itself)

as standard these engines have a huge capacity to absorb and radiate heat. without the radiator being involved in the equation. I only once got worried about my engine being warm when it was stop start traffic for 5 hours on the M6 which they had closed ahead of my location and it was at 90 on the gauge, with no fans fitted.. 5 minutes worth of being off and it had dropped an apparent 10degrees.

[Ruan]

I've found on genuine stats (from testing with pans of water...), the thermostat will tend to start opening at ~80*C and be a bit open by ~83*C... The reason they jump a little when the thermostat first opens is because there's not much bypass flow to ensure the thermostat actually receives the hot water to allow it to open. Soon as the block water starts actually moving, the actual localised water temperature hits the thermostat housing which was full of cooler, slowly moving water up until the thermostat opens.

Correct that the TU3s do have an 89*C thermostat. Note that the GTi6 infact has an 83*C thermostat, same as a HDi.

[JTaylor2005]

You know we have those glow plugs that are in the coolant. Do they work throughout the time the car is on? Just boosting the temp to keep it at an efficient temperature?? Specially when cruising at a steady pace with high air flow and no real load on the engine?

[Midnightclub]

I believe they're only on for either a short period of time or until the car reaches a certain temperature. That said, most are probably long dead by now

[Paul_13]

From memory I remember someone saying they pulse up to temp and for 15 mins after.

I could tell pretty clearly on mine as the alternator is f*cked. The lights dim on and off for a while until up to temp

[HDi--Power]

The coolant glow plugs pulse on and off constantly, even when up to temp.

[JTaylor2005]

Haha fair enough. Well quick update. Having bought and fitted my new gates thermostat (83c opening temp) I drove to work today with took about 35 minutes. All the way it sat at pretty much spot on 90c on the gauge. Varied up and down on the gauge within the 90c white mark. I made sure I bled the system after warming it up as well so its all working corectly.
That is without the cardboard on the front by the way.

Also I noticed when fitting my old star that the rubber seal was slightly too small for the hole so the stat was slightly loose. This one fit nice and snug and tight as there was 3 to choose from with the gates stat so I picked the snug fitting one.

[MY95]

Would be interesting to see the difference in MPG your getting a 90 Jack As well as what temp it would be showing on the gauge if you now took the cardboard away.

[JTaylor2005]

Sorry the cardboard has actually gone now. I am just running it normally with a well seated tight fitting gates thermostat. It runs spot on 90c on the gauge. Not sure what that equates to real temp wise but its up about 7c normal running temp from the previous thermostat without the cardboard.