HDi Running Temperature

[me-tm]

Quick question for you lot.

My HDi shows just above 70 on the temp gauge when it's warmed up, and the needle is completely off the bottom when it's cold (but that's normal anyway).
My question is, is 70 celsius or so correct? My old ph1 XUD ran at just over 80. The heaters still behave themselves and it all seems ok, but I'm just wondering if maybe the thermostat is slightly stuck open and it should be running a bit warmer, i.e. more like 80 celsius like the old XUD.

Thanks in advance!

[Mattcheese31]

my Hdi van runs at that temp so i would say yes that's fine, direct injection is cooler . .

[me-tm]

Yeah, got an answer in the chat box just after I posted this thread.

Derp!

I'm such a car hypochondriac though, maybe that's due to owning Peugeots.

[happypug]

Hi mate.
My Hdi has had a new rad, thermostat, and now runs at 80c all the time. Previously ran at 72c. Best not to worry, as in my case new is not better for temp.
Happy pug

[Poodle]

These engines do run cool, but not that cool lol. 79* is normal running temperature for a healthy hdi, anything less and they lose efficiency hand over fist. I'd suggest checking out your thermostat, it's probably stuck open. You too, Matt.

[titch]

I have a scan gauge in my car, and the water temp on there once warmed up is always between 78 -80

[C.A.R.]

Does anyone know if the temperature display is linear in our cars? It's very unusual for a modern car to have such a setup, as it is believed that drivers would get concerned, so they tend to read between two extremes and display a safe figure, only reading the actual temperature once the 'safe' parameters have been exceeded. At least, that is what I am lead to believe...(awaits Ruan correction)

[Toms306]

That's for VAG cars Chris, not cheap old Peugeots. Or Vectra's if you were interested, I'd prefer that it sat it 90 like the Mk4s used to, regardless of the actual temp.

[Ricky]

Mine rarely reaches 80 in this weather with a new stat and coolant.

[Jonny81191]

mine has a sticky thermostat and rarely exceeds 70*

my 406 on the other hand, sits at a steady 90* on the gauge. I'm tempted to believe it TBH, the heaters are burning hot!

[Poodle]

The 306 has a linear gauge according to my scangauge, it's not really a modern car any more lol.

Barely reaching 80 is right, it should peak at 80 then drop a couple of degrees as the stat opens.

I think the later engines (406/307/etc) were fitted with higher temp thermostats as a matter of course, probably to increase the efficiency. I've got a 307 one here that I haven't fitted yet, that one doesn't open until ~90*.

[Mattcheese31]

These engines do run cool, but not that cool lol. 79* is normal running temperature for a healthy hdi, anything less and they lose efficiency hand over fist. I'd suggest checking out your thermostat, it's probably stuck open. You too, Matt.

no, brand new stat in mine mate, didn't make it past 60 before that lol . . . .mine runs at about 74ish remembering that it has a fmic . .

[DeeTurbo]

I think the later engines (406/307/etc) were fitted with higher temp thermostats as a matter of course, probably to increase the efficiency. I've got a 307 one here that I haven't fitted yet, that one doesn't open until ~90*.

Are you going to be fitting that stat soon as I'd be very interested in the results?

[C.A.R.]

That's for VAG cars Chris, not cheap old Peugeots. Or Vectra's if you were interested, I'd prefer that it sat it 90 like the Mk4s used to, regardless of the actual temp.

It's a lot of modern cars unfortunately

It's to stop people getting into a blind panic when the needle goes a bit higher than they are used to. My Celica had it (albeit in digital form) and the MX5 had it too (from 1994!)

Poodle says it's linear, I'm inclined to subscribe to that since it seemed to wander in traffic this summer...

[Jonny81191]

Interesting alex, ill be doing that asap then.

[tigerstyle]

Was going to make this very thread soon also, Mine sits just above 70°C (iirc) and I've a feeling it should be a little hotter, for the efficiency and all!

[Toms306]

That's for VAG cars Chris, not cheap old Peugeots. Or Vectra's if you were interested, I'd prefer that it sat it 90 like the Mk4s used to, regardless of the actual temp.

It's a lot of modern cars unfortunately

It's to stop people getting into a blind panic when the needle goes a bit higher than they are used to. My Celica had it (albeit in digital form) and the MX5 had it too (from 1994!)

Poodle says it's linear, I'm inclined to subscribe to that since it seemed to wander in traffic this summer...

Oh fair enough then, out of all the cars I've owned so far only the Golfs have had that sort of system!

The 306 definitely doesn't, used to watch the 1.8 temp bounce around with the high speed fans on and off in traffic. And even the Vectra one never hits 90, sits between 80 and 85 eventually (and proved with scan tool), as said though I would prefer it to sit at 90 so it looked right.

[Poodle]

no, brand new stat in mine mate, didn't make it past 60 before that lol . . . .mine runs at about 74ish remembering that it has a fmic . .

Oh really..? Odd, not seen that before. Mine has an intercooler too, really shouldn't make a difference to what the water temp is lol.

Deeturbo, i've had it for about six months already, so probably not soon tbh. Will all be recorded in my project thread when i do though, i've got a spare stat housing lying about so i suppose i haven't got an excuse not to... This weekend then, Jonny?

[Alan_M]

Servicebox says it's an 83'C stat on an HDi.

[Dum-Dum]

I have a scan gauge in my car, and the water temp on there once warmed up is always between 78 -80

Same as this.

[Mattcheese31]

no, brand new stat in mine mate, didn't make it past 60 before that lol . . . .mine runs at about 74ish remembering that it has a fmic . .

Oh really..? Odd, not seen that before. Mine has an intercooler too, really shouldn't make a difference to what the water temp is lol.

Deeturbo, i've had it for about six months already, so probably not soon tbh. Will all be recorded in my project thread when i do though, i've got a spare stat housing lying about so i suppose i haven't got an excuse not to... This weekend then, Jonny?

you reckon? . . . i would have thought it would make a fair difference, lower charge temps has to = lower running temps surely . .

[DeeTurbo]

you reckon? . . . i would have thought it would make a fair difference, lower charge temps has to = lower running temps surely . .

Lower charge temp, denser air, more power, more heat.

[Poodle]

Yeah, but the stat will still stay closed until it hits 80 - or rather 83, as Alan says - regardless of what the rest of the engine is doing. If it falls below 80 the stat should close again so the temp would still stay up, that's the whole point lol.

I guess the siemens systems could have a different stat, but that seems a bit odd to me...

[Mattcheese31]

you reckon? . . . i would have thought it would make a fair difference, lower charge temps has to = lower running temps surely . .

Lower charge temp, denser air, more power, more heat.

say what?

[Poodle]

That's correct, but also irrelevant. The whole point of the thermostat is to regulate temperature - if you can affect how it works by changing other bits of the engine then it's not fit for purpose. Do you see what i'm saying?

[DeeTurbo]

say what?

So the lower the charge temperature, the more dense the air is going to be ie more oxygen is going to be going in to the cylinders so the hotter the burn is going to be, so the more heat is going to be produced and the harder the cooling system will have to work.

[Mattcheese31]

say what?

So the lower the charge temperature, the more dense the air is going to be ie more oxygen is going to be going in to the cylinders so the hotter the burn is going to be, so the more heat is going to be produced and the harder the cooling system will have to work.

yeah but any uncombusted fuel makes it inefficient, and therefore hotter no?

[Poodle]

No, unburnt fuel doesn't produce heat, its the actual burning that produces heat. It will actually cool the chamber, much in the same way spraying water at something cools it.

[Mattcheese31]

No, unburnt fuel doesn't produce heat, its the actual burning that produces heat. It will actually cool the chamber, much in the same way spraying water at something cools it.

so you're telling me that an XUD coaling to high hell is running cooler than one that is combusting the fuel instead? . . . .

[Poodle]

Assuming the same amount of fuel is being pumped in, yes, that's exactly what i'm saying. But why take my word for it, there's this awesome place where you can find information about anything from why the sun comes up to why steve's missus is so fit, you might even have heard of it: google..? :p