Meriva temp gauge and rado q's

Hehe. ;-)

Cheers, T i m

When for a run up to MK yesterday and round and about and rarely saw the temperature gauge reach the 80 mark. Bowling up and down the M1 at ~70mph it was generally below the actual first mark on the gauge. Ticking over at the lights or in stop -start traffic saw it get nearer the 80 deg point. The cabin heater output feels reasonably 'hot' though?

I just tried that (I did a short trip so the engine was already 'warm' then let it tickover outside the house and it seems like the fan is cutting in at an indicated 90 DegC (but it's difficult to tell as the fan is pretty quiet and I can't be in both places at once). For sure I've never seen the gauge indicate more than about 92 DegC.

So, is that sufficiently short of the 100 to suggest it's the temperature sensor as it might be unlikely for the thermostat to have gone wrong *and* the fan temperature sensor switch (depending on where the fan get's it's input from etc)?

Cheers, T i m

It sounds as though the gauge is reading lower than the actual temp.

you can test the sender with a multimeter and a thermometer plus some warm water. at 20degrees c it should read 2200 ohms and at 80 degrees it should read 350 ohms.

Thanks, very handy.

Are they the values for this particular vehicle / engine or are they pretty common across all?

Cheers, T i m

that is the data for your exact vehicle from autodata

Brilliant, thanks.

Now to find the sender .... ;-)

Cheers, T i m

Old one:

On a 10 mile trip home tonight at ~60 mph the temperature gauge stayed below 70 DegC.

I'm going to tape an external temperature probe on the top hose tomorrow and see what that shows on a short trip.

Would I be right in thinking any instant / gradual rise in temperature would indicate a stuck open stat (not just the bleed)?

Cheers, T i m

the temp gauge should come up to midway within about a mile of a cold start. if you start the car from cold and grope the top hose it should stay practically cold until a sudden rush of hot as it opens for the first time. many thermostats no longer have a bleed hole in them. the engine designers usually incorporate a high up bleed/return tube to the header tank. this was not really an option when you only had a radiator.

Ok, well that it certainly does not.

Understood. I'll do that but with the external temp gauge thingy. ;-)

Ah, ta.

Is that the one that seems to constantly circulate some coolant?

Understood.

I was actually thinking back to the days when I would have sat looking into the top of the rad at the water just idly drifting about, then seeing it start to flow across the top of the rad as the stat opened. In fact, I can still do that on the MkII Escort based kitcar. ;-)

Thanks very much again.

Cheers, T i m

p.s. I've asked my mate in the garage up the road to give me (well Mum) a price for doing the lot (belt, pump, stat etc). Looking in there reminds me of the gynaecologist who wallpapered his hallway through the letterbox ... ;-)

that is an easy vehicle compared to some :)

I'm sure it is but I bet it isn't as easy as the Pinto lump. ;-)

How would it be compared to doing the same on the 1.4i Vauxhall (I did her Belmont water pump, stat and belt a while back) or the belt on the old Rover / Pug 1.9 diesel?

We did pop out in the Meriva today but only to pick up a concrete post and some cement. I'm not sure what would do my back the most, the post or playing with engines stuck in sideways. ;-)

Cheers, T i m

it is no different to the belmont (assuming you have the single cam engine?) It just looks worse. easier than the peugeot/rover lump.

Yup.

Working though that hatch rather than a big bonnet etc?

Oh, ok.

Cheers and thanks again.

T i m

Ok, I've been monitoring it over a few days / trips and it seems consistent at least. If you are moving at any reasonable speed the needle doesn't even enter the gauge (so sub 70 DegC indicated).

I've put the old temp sensor in a cup of as near to boiling water as I can get, alongside a decent thermometer and the car gauge may read about -5 of that. So, when thermometer reads 90, gauge reads ~85.

Right, I managed to get a chance to do that this morning from properly cold.

Quickly after start (maybe 60 seconds) the small recirc hose that goes into the header was starting to run warm. A few mins later (maybe 5?) the thermostat housing / output stub (where it enters the top hose) started to hot to the touch (but you could easily keep your fingers on it) and then started to flow though the top hose / rad. The car gauge was still showing sub 70 DegC. We then had to go somewhere and as we pulled away it was holding at an indicated 80 but soon dropped to near

So, could we be looking at a 'lazy stat'. One that is functioning but just opening a bit prematurely?

I need to calibrate my external thermometer I've currently got taped round the car and with the sensor on the recirc hose (rad a max of 60 Deg in traffic earlier) and I'll try to attach it to the thermostat housing / top hose as best I can (so I can just drive away and still monitor it).

Sitting in traffic earlier I put the heater and fan on full and saw it bring the temperature from under 90 (where the electric fan cuts in) to about 75.

I picked up the owners manual from Mum on my way back and for the Z16SE lump it says '8 years or 80K miles' for the cambelt / tensioner (currently on 45k). Given this it's just 8 years old and I can't see any sign of it being done in the service records then maybe it wouldn't be a bad idea in any case?

Whilst looking at the engine this morning it seems there is a blanking plate where an EGR valve might be (on top of the inlet manifold?). ;-)

OOI, may I ask what Autodata says for the temp for the stat on those please (04 Meriva 1.6).

Cheers and thanks again for your time.

T i m

'Thermostat opens 92C'

Chris

Thanks very much Chris.

So I wonder if that actually means 'opens' or 'is fully open' at 92 (assuming it's not a digital action).

I've just been out there again with a decent thermometer stuck on the outside of the thermostat housing outlet where it joins the top hose (wedged in with some foam wrapped in silver foil) and it was reading about 85 DegC when the fan kicked in.

However, I'm pretty sure it was much less when the water started to flow round the rad. I'll keep and eye on the rate of change of temp via the external probe when I go out again later (display stuck on dash) .

Cheers, T i m

Generally, it means 'starts to open'.

I'm sure you have your reasons, but a new thermostat and seal is £7.86; is it really worth the effort you are putting in to this?

Chris

Ok, thanks.

(I do ..) ;-)

Well, if it were only a stat and seal then, no, of course not. However the other bits, like cambelt, tensioner, water pump and the time for the guy to do it (most has to come off apparently to do the job, all a bit beyond me as a side_of_the_road job) are around £250.

Now, to add more 'value' to that the owners handbook states '80K miles or 8yrs on the belt and tensioner' and as it's an 04 (even with only

Had it been the Kent powered kitcar or anything else where it was both easy and 'just' a gasket and stat, for sure it would have been done by now. ;-)

Until looking in the owners guide (only picked it up today) I had no facts re the cambelt so that 8 years thing sorta clinches it (even if 'age' doesn't often factor highly in cambelt failures?).

I generally (also) like to a) determine *exactly* what's going on and b) like to be pretty sure I'm doing stuff (both because of the time and the money) for good reason. The car is actually running ok (I'm about to take the first full to full fuel / miles measurement so may be able to qualify that further) but as it's potential new owner (Dad had it from new) I don't yet have any feeling about what is right or typical or not. Do I simply accept the 'nah, it's ok, all Vauxhalls are like that' and just ignore it or try to make some logical sense of it all? Had it not been 'Dads car' and / or hope to keep it for a good while then maybe I'd not bother.

Assuming the temperature gauge is relevant and accurate, then my first, immediate and off_the_cuff conclusion was 'thermostat stuck open'. Learning what was involved and therefore the cost made me be a bit more cautious.

Given the money and time I'd have several temperature probes all over the cooling system and a datalogger capturing timed data! ;-) [1]

'You can manage what you can measure. ;-)

Cheers, T i m

Just down on the red. Reasonable mix of motorway (~65 mph) and local running around. I've also been trying to take it gently.

71.7 x .22 = 9.2G

Big shock after the old 218SD Rover (around 47 mpg) and more reminiscent of the 2L GL Sierra Estate!

So, I wonder if that's not as good as it could (should?) be because it's might be running too cool (on a run especially)?

Cheers, T i m