'04 C5 V6 - "Engine Coolant Temperature Too High" (T'stat?)

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Ben82
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'04 C5 V6 - "Engine Coolant Temperature Too High" (T'stat?)

Post by Ben82 » 03 Dec 2012, 18:41

Hi All,

I'm a Brit living in Sweden with a previously German imported C5, I've had it for about 4 months now, and had a range of issues, most were not made aware of by the seller (but they may not have known):
- Cambelt Change (one that I did know about, just not how expensive it would be!) Done about 2 months ago
- Brake Pads Change - Done about a month ago
- Random Warnings (which I think maybe down to the Battery!)

But most of all recently I've had when it's been sub-zero temperatures, I've had the warning "Engine Coolant Temperature Too High", which would disappear after a bit... Took it into the garage (Citroen Specialist - not a dealer) when having the brake pads changed... they changed the sender (well was a green thing anyway), and at the time it was hard to consistently get the issue.

This weekend we've had a very cold snap (-18C this morning), and it's been happening a lot, and only seems to occur with driving over 70km/h for at least a few minutes, under it doesn't seem to occur as much.

Took it back in today for them to have another look, and picked it back up around 4pm, they said the only thing left is changing the thermostat, which they can do tomorrow, but want about 1900SEK for (about £180!), one issue is their part supplier seems rather expensive (the thermostat is about 450SEK ~£42). Which I could get shipped in from France for almost half the cost. He said it was a fair bit of work hence the cost.
I asked if I should stop whenever it comes up, and he said "Nope, just drive!", which is correct it does disappear and come back, and the temperature gauge is all over the place (Blue - beeping, jumping to half way, then shooting up to Red, and doing the same when it "cools down" - Red: Dips quickly down to half way, then fairly quickly back to blue)

It is something I'm considering doing myself, however my main issues are:
1) It's Freezing!! and don't really have a proper spacious garage for keeping me warm - I have a parking garage, but it's small, and would probably need to use my 900W heater to try to help keep me warm, and would probably need to have the car slightly outside the garage (for light, and being able to get around the front of the car, along with being able to jack it up if need be)
2) Don't currently have the tools to do so (though looking at buying a set anyway)
3) If the coolant needs to be replaced at the same time, then I do not have a hose to flush it out and it's that's an extra cost.
4) There seems to be a clicking sound coming from the driver's side (LHD) around the time when it occurs, but can't locate exactly what it is making the noise - Before knowing where abouts it was I suggested maybe it was the water pump, but I don't believe that's located there.

So my main questions are:
1) Is it likely to be the Thermostat? The engine does not feel warm to the touch (main engine, radiator cap, anywhere really), and don't expect it to be when it's -18C outside and the car has been running for less than 10 minutes.
2) If it is, will I need to replace the coolant at the same time? (Would be nice not having to, but I'm not sure what coolant is already in there, and from what I've read, you can't mix and match)
3) is it "a lot of work" on the v6 to do so? (and is it fairly similar to: http://www.youtube.com/watch?v=vssQVTSWLGo" onclick="window.open(this.href);return false; ?)

Or is there more to it and worthwhile getting them to do it? I estimate I need to spend about £25 for the Thermostat, and about £50 in Citroen/Peugeot "Glykol" (it says the cooling system volume is 12 litres, and I worked out the cost for 6 litres - ready mixed glykol (12L) would cost about £72), from what I can tell I don't need anything else? so that's comes to between £75 and £100. (I don't know if they're replacing the coolant though, at those prices it doesn't seem likely).

Thanks In Advance

Ben

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CitroJim
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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by CitroJim » 03 Dec 2012, 19:03

Hi Ben and welcome to the forum :-D

Umm, well. Swapping the thermostat in a V6 is a tricky old job even in a warm garage due to its location.

To be honest I don't believe it is as normally they're pretty reliable and also they move very slowly and too slowly I would have thought to cause such rapid fluctuations on the temperature gauge as you are seeing.

The green sensor they changed is the coolant temperature sensor for the engine ECU and may not drive the temperature gauge, that in a Xantia with the same engine is the job of the blue sensor which is screwed into the side of the rear cylinder bank underneath the throttle body. It's hard to get at and it's buried in the 'plumber's nightmare' of coolant pipes that abound under there. It's therefore susceptible to getting wet from any small coolant leaks and causing a bit of corrosion on the electical connector...

So, my first move would be to have a look at the blue connector and check/clean its connector.

To prove if the engine is overheating or not the best way, and I'd hope the garage has one, is to look at live coolant temperature data on a Lexia diagnostic machine whilst the car is exhibiting the symptoms.

As I say, I'd think this is electrical more then it is mechanical...

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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by Ben82 » 03 Dec 2012, 20:29

Hi Jim,

Thanks for the welcome and confirming that I'm not going mad... I feel like if it was a mechanical issue, it would be a far larger issue, i.e overheating regardless of outside temperature, and actually feeling hot, along with actually pushing out hot air from the inside fans, so good to know.

I don't believe they have a Lexia, one thing I asked for was having the headlights on during the day (legal requirement here in Sweden mixed with a forgetful Brit wouldn't bode well with the ~£70 fine each time you get caught ), and they took it to the local dealer for them to hook it up and see if they could turn it on there, but they couldn't, so opted for some black electrical tape over the light sensor (it's a cheap solution that works.... most of the time!)
Did strike me as a bit odd that they didn't have one considering being a Citroen specialist, but the Dealership is only 2.5km away, and who knows what kind of agreement they have.

I have been considering getting one of the Lexia's off ebay, since it could be quite handy to have around,for this along with the potential battery issue... And I do intend on replacing this C5 with a newer model a few years down the line, and it could come in handy then too.

I'm guessing despite the plumber's nightmare, it's a far better and quicker job than replacing the Thermostat?

Is it worth putting my 900W cabin heater under the engine tonight to warm up the area around the blue sensor? (it's on a timer to kick in about 6:25am and with current temperatures will turn off after about 75 minutes), though with the temperature due to be around -21C in the morning, I don't think the warm up will last very long.. Have considered getting and installing the "full works" winter kit for the car (cabin outlet, engine heater, and battery charger), which may mitigate my issues, but isn't cheap (another issue with it being an import, as most Swedish cars have at least the cabin outlet as standard).

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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by CitroJim » 03 Dec 2012, 20:46

Investing in a Lexia will pay for itself in no time Ben. Take the advice on this forum as to which one to get as there are Lexias and Lexias - they don't all seem to be equal... There's a big sticky at the top of the page here and the later posts contain some new recommendations and some guides to using the latest software.

I like the black tape modification :lol: At least with your own Lexia you'll be able to do it properly!

Yes, I'd say the blue sensor is easier to get to then the thermostat - its connector certainly...

If you can get a bit of warmth to the area safely then that's not a bad idea at all. It will help dry out any moisture in the area and if the fault then clears you'll have a good clue that it's electrical in nature. If I read correctly it tends to clear when the engine and its surroundings are nice and warm.

If the engine was really seriously overheating then I'd expect coolant loss - I assume you've not lost any?

Sorry if this is egg-sucking but the coolant in there is well up to strength I trust and not freezing to mush and small lumps of ice when really cold - mushy coolant in the rad might well reduce circulation but I'm sure you've thought of this already...

They are tough engines but will let head gaskets go if they seriously overheat for an extended period and the coolant drops too low - the result can be rather spectacular when they do - they're not gentle or subtle!

keep us posted on how you get on :wink:

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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by Ben82 » 04 Dec 2012, 09:20

Hi Jim,

Thanks, I haven't personally checked the coolant, but I would hope that's one of the things they would have checked yesterday, before deciding to go with the thermostat.

Took your suggestion to them this morning, and seemed rather insistent that it was the thermostat, due to it not blowing out hot air out into the cabin. I did ask them to check the blue sensor first beforehand, which they said ok to but I don't feel that confident they will. (I spoke to a different guy than the one I was talking to yesterday, as he was out, and he wasn't sure if that was checked) He also said they spoke with Citroen and they said that it was probably the thermostat. He also said "if it isn't the thermostat then it's something with the engine, that would be more expensive"

It seems like conflicting advice too, if it was the thermostat, then surely it isn't safe to carry on driving? And also would mean the engine would carry on heating up? and just slowing down would not be sufficient for it to drop from "Far too high" to "Still as cold as when you started!" in a matter of seconds (even with the outside temperature!).. And would have thought, if it was the thermostat, the temperature gauge would gradually rise as it heats up, but that's not the case.

I also noticed this morning, that when it is moaning, the fan is going ten to the dozen, and you hear it stop when the car stops moaning.

Spoke about the Lexia too, which he did seem a little cagey on... I asked if it was worth me taking it to the dealer for them to drive it about with the Lexia plugged in, his response seemed to be "oh no, we've already asked that, and they wouldn't!" - handy! All the more reason for me to get one then.

Did have half a mind to leave there with the car, and tell them to leave it. I'm back in the UK in a couple of weeks until new year, so gives me time to get a Lexia, only problem would be the stop-start journey to the airport, however I could take public transport instead, but that's not too fun in this weather.

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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by Chris570 » 04 Dec 2012, 11:47

either i'm being stupid here or the cooling system is laid out differently on your car. But if the thermostat is the problem i don't see how that will keep the heater matrix cold. my initial suspicion is not enough antifreeze and allowing the the matrix to freeze and radiator to do the same. I've seen it before and it looks exactly like a HG going (if you watch the temp gauge) as it goes up and down like a whores drawers. This was because of the ice breaking off and rejoining the cooling system causing a drop in it's temp.

just a thought but i'd squeeze the coolant pipes prior to starting to see if they are frozen....

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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by Ben82 » 04 Dec 2012, 18:26

Well I went back to collect the car, and they said it was the Thermostat was stuck open! He showed me the removed thermostat, and it did look open...

I guess the main test will be tomorrow after it's been left cold overnight (when I picked it up the temp gauge was fairly central, so must have been running for a while).

I'm bemused, as to how an open thermostat, would cause a message saying the engine coolant temperature was too high!

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Re: '04 C5 V6 - "Engine Coolant Temperature Too High" (T'sta

Post by Mandrake » 04 Dec 2012, 19:49

Chris570 wrote:either i'm being stupid here or the cooling system is laid out differently on your car. But if the thermostat is the problem i don't see how that will keep the heater matrix cold.
That's what I thought at first too, but if the thermostat is stuck open it would take the engine a long long time to warm up in -20 ambient conditions...in fact it may never warm up much. It's the fact that the radiator flow is normally blocked by the thermostat when cold that allows the engine to heat up quickly and heat the cabin heater quickly...so I can readily believe the heater wouldn't work in those low temperatures with a thermostat stuck open.
my initial suspicion is not enough antifreeze and allowing the the matrix to freeze and radiator to do the same. I've seen it before and it looks exactly like a HG going (if you watch the temp gauge) as it goes up and down like a whores drawers. This was because of the ice breaking off and rejoining the cooling system causing a drop in it's temp.

just a thought but i'd squeeze the coolant pipes prior to starting to see if they are frozen....
Does sound a bit like pockets of coolant are freezing blocking the flow doesn't it...I'd be making sure the coolant was flushed and the mixture is nice and strong for such low temperature conditions, as the consequences of blocked coolant flow could be rather serious...