Do modern cars have thermostates?

[Pete (archive)]

Hi All

As the title says do modern cars have traditional thermostats or is it looked after by the computer? My Meriva temperature gauge is going up and down. Until recently it was fixed at approx 90degC going up only on supper hot days sitting in traffic. Now it sits below 80degC when cruising along and creeps up in traffic to 90 and beyond. at approx 100 the fan comes on and it seem to stabilise coming right down to <80 as soon as you get moving again. With this I expect it will over heat when the summer comes. I have had a look around under the bonnet and can't see a traditional thermostat housing. I expect If there is one I am looking in the wrong place any hints.

Also and it may be connected the light of a car with a spanner through it lights up after a few mins running could this be the computer telling me it the engine is not as hot as it would like?

Pete

 

[airsmoothed]

Hi All

As the title says do modern cars have traditional thermostats or is it looked after by the computer?

Also and it may be connected the light of a car with a spanner through it lights up after a few mins running could this be the computer telling me it the engine is not as hot as it would like?

Pete

Yes, pretty much all modern cars still have thermostats, some of them are electronically actuated via the ECU, rather than the old wax canister style. No idea if the Meriva is old style or new style. FWIW most modern Vauxhalls do seem to be overcooled to me, my wife's Zafira sits at 80C unless its working really hard - these days the engine temeprature guage is probably driven by the ECU, so need not bear any resemblance to the actual engine temperature.

In terms of the spanner, it could be anything, you need to get the codes read. Any vaguely competent auto electrician should be able to do that for 30 - 40 quid, a VX dealer will almost certainly want upwards of 60 quid for the 5 minutes required to plug in laptop and read codes.

 

[John (archive)]

On another tack, I have a 2006 Zafira 1.6 petrol that doesn't have a temperature gauge or any indicator that I can see. I presume if my engine gets too hot I would be notified by a light etc. in the dashboard area.

Cheers

John

 

[Pete (archive)]

I hear what you say, The engine seems to get hot even when it is showing "cold" i.e. the Heater works, I think I will have to get the codes read.

Pete

 

[adder1969]

I hear what you say, The engine seems to get hot even when it is showing "cold" i.e. the Heater works, I think I will have to get the codes read.

Cold while cruising would suggest the thermostat is stuck open while hot while stationary would suggest the opposite. Is there water in it?! One of my cars would run hot then spew the water out then run "cold" as the water stopped making contact with the sensor.

Sounds like you might have a sensor problem if the "check engine" light is coming on.

 

[Abo]

In terms of the spanner, it could be anything, you need to get the codes read. Any vaguely competent auto electrician should be able to do that for 30 - 40 quid, a VX dealer will almost certainly want upwards of 60 quid for the 5 minutes required to plug in laptop and read codes.

You can buy a code reader off eBay e.g.

http://snipurl.com/obd2cheap

 

[Basill]

They do,
I have a New model vectra. Just recently it would take ages to get hot ( on the temp guage) and then drop to cold when driving. A new thermostat cured it. Mine was probably stuck open, yours maybe the other way?

B

 

[Brim]

On another tack, I have a 2006 Zafira 1.6 petrol that doesn't have a temperature gauge or any indicator that I can see.  I presume if my engine gets too hot I would be notified by a light etc. in the dashboard area.

Cheers

John

As it shows in the owner's handbook page 37 there is a warning symbol on dash for when it is getting too hot.

 

[Pete (archive)]

Hi All

Thanks for the replies,

Codes read yesterday - dealer said it was Temperature control Resistor at fault. Non in stock - ordered overnight Fitted today, Problem still there!

Further investigation is "possible ECU failure" £569

with no confidence this is the final solution check.

Called it a day I will put up with the warning light

Cost to me 90 smackeroos only difference warning light now on 100% of time!

Looks like time to chop car in for another

Pete

 

[airsmoothed]

Hi All

Thanks for the replies,

Codes read yesterday - dealer said it was Temperature  control Resistor at fault. Non in stock - ordered overnight Fitted today, Problem still there!

Further investigation is "possible ECU failure"  £569

with no confidence this is the final solution check.

Called it a day I will put up with the warning light

Cost to me 90 smackeroos only difference warning light now on 100% of time!

Looks like time to chop car in for another

Pete

- Show quoted text -

In general ECUs are pretty reliable in my (limited) experience, however Vauxhall decided it would be a great idea to bolt the ECU onto the side of the engine, so it gets cycled at extremes of temeprature and fails :-(((. What a dumb ass idea. I'm not sure if this applies to the Meriva or not, certailnly many VX 1.8 engines are like this.

When I wanted to check the coolant temeorature sensor out on my old Omega I actually disconnected the ECU and checked the resistance at the end of the loom where it connects to the ECU, to make sure the cabling was OK, as well as the sensor itself.

As a last resort there are ECU remanufacturing companies around, bba reman. for example.

http://www.bba-reman.com/catalogue/Index.aspx?category=29

 

[airsmoothed]

In general ECUs are pretty reliable in my (limited) experience, however Vauxhall decided it would be a great idea to bolt the ECU onto the side of the engine, so it gets cycled at extremes of temeprature and fails :-(((. What a dumb ass idea. I'm not sure if this applies to the Meriva or not, certailnly many VX 1.8 engines are like this.

When I wanted to check the coolant temeorature sensor out on  my old Omega I actually disconnected the ECU and checked the resistance at the end of the loom where it connects to the ECU, to make sure the cabling was OK, as well as the sensor itself.

As a last resort there are ECU remanufacturing companies around, bba reman. for example.

http://www.bba-reman.com/catalogue/Index.aspx?category=29- Hide quoted text -

- Show quoted text -

Thinking about your symptoms a bit more, I would expect a dodgy coolant temperature sensor to cause problems when starting, rather than running. I don't think this sensor plays much of a part in the running of the engine once it is up to temperature. The action of the cooling fan is driven from a sensor in the rad; at least on all the VXs I've owned, admittedly all 2000 or earlier cars i.e. X series engines not Z. Maybe on the Meriva they use one sensor for both functions, hopefully someone here knows for sure?

There are VX forums around where it might be worth asking about your problems, for example I use this one a bit:-

http://www.cavweb-forums.co.uk/

Alternatively this is a good forum for technical questions on all makes:-

http://www.honestjohn.co.uk/forum/threads.htm?f=4

 

[Pete (archive)]

Hi

I my all be it limited experience ECUs don't give much trouble they either work or not. it is unlikely that just the temp sensor would be faulty with nothing else even playing up. For the record the sensor changed was V0093175501.

I have looked at the web page for recon ECU and £166 sounds better than £569 MD fitted.

The more I think about it I believe it is not the sensor but the actual thermostat that controls the water. I am just not sure where to look for it the "top hose" disappears behind the cam belt cover with no obvious bump where a thermostat might be. I think the engine is the same as a old shape Astra so I might pop down the library and have a gander at a Haines manual to see if this is any help. trouble is I run a Newish car for the one reason I thought my climbing under car days were over!

Pete

Hi All

Thanks for the replies,

Codes read yesterday - dealer said it was Temperature control Resistor at fault. Non in stock - ordered overnight Fitted today, Problem still there!

Further investigation is "possible ECU failure" £569

with no confidence this is the final solution check.

Called it a day I will put up with the warning light

Cost to me 90 smackeroos only difference warning light now on 100% of time!

Looks like time to chop car in for another

Pete

- Show quoted text -

In general ECUs are pretty reliable in my (limited) experience, however Vauxhall decided it would be a great idea to bolt the ECU onto the side of the engine, so it gets cycled at extremes of temeprature and fails :-(((. What a dumb ass idea. I'm not sure if this applies to the Meriva or not, certailnly many VX 1.8 engines are like this.

When I wanted to check the coolant temeorature sensor out on my old Omega I actually disconnected the ECU and checked the resistance at the end of the loom where it connects to the ECU, to make sure the cabling was OK, as well as the sensor itself.

As a last resort there are ECU remanufacturing companies around, bba reman. for example.

http://www.bba-reman.com/catalogue/Index.aspx?category=29

 

[airsmoothed]

Hi

I my all be  it limited experience ECUs don't give much trouble they either work or not. it is unlikely that just the temp sensor would be faulty with nothing else even playing up.  For the record the sensor changed was V0093175501.

I have looked at the web page for recon ECU and £166 sounds better than £569 MD fitted.

The more I think about it I believe it is not the sensor but the actual thermostat that controls the water. I am just not sure where to look for it the "top hose" disappears behind the cam belt cover with no obvious bump where a thermostat might be. I think the engine is the same as a old shape Astra so I might pop down the library and have a gander at a Haines manual to see if this is any help. trouble is I run a Newish car for the one reason I thought my climbing under car days were over!

Pete

In general ECUs are pretty reliable in my (limited) experience, however Vauxhall decided it would be a great idea to bolt the ECU onto the side of the engine, so it gets cycled at extremes of temeprature and fails :-(((. What a dumb ass idea. I'm not sure if this applies to the Meriva or not, certailnly many VX 1.8 engines are like this.

When I wanted to check the coolant temeorature sensor out on  my old Omega I actually disconnected the ECU and checked the resistance at the end of the loom where it connects to the ECU, to make sure the cabling was OK, as well as the sensor itself.

As a last resort there are ECU remanufacturing companies around, bba reman. for example.

http://www.bba-reman.com/catalogue/Index.aspx?category=29- Hide quoted text -

- Show quoted text -

What year / engine is it? I do have a set of VX TIS2000 service disks on the laptop at home, not very user friendly but most of the tech.
info is on them. somewhere.

 

[Pete (archive)]

Engine type according to car ID plate = Z10SE/02PP4893

Hi

I my all be it limited experience ECUs don't give much trouble they either work or not. it is unlikely that just the temp sensor would be faulty with nothing else even playing up. For the record the sensor changed was V0093175501.

I have looked at the web page for recon ECU and £166 sounds better than £569 MD fitted.

The more I think about it I believe it is not the sensor but the actual thermostat that controls the water. I am just not sure where to look for it the "top hose" disappears behind the cam belt cover with no obvious bump where a thermostat might be. I think the engine is the same as a old shape Astra so I might pop down the library and have a gander at a Haines manual to see if this is any help. trouble is I run a Newish car for the one reason I thought my climbing under car days were over!

Pete

In general ECUs are pretty reliable in my (limited) experience, however Vauxhall decided it would be a great idea to bolt the ECU onto the side of the engine, so it gets cycled at extremes of temeprature and fails :-(((. What a dumb ass idea. I'm not sure if this applies to the Meriva or not, certailnly many VX 1.8 engines are like this.

When I wanted to check the coolant temeorature sensor out on my old Omega I actually disconnected the ECU and checked the resistance at the end of the loom where it connects to the ECU, to make sure the cabling was OK, as well as the sensor itself.

As a last resort there are ECU remanufacturing companies around, bba reman. for example.

http://www.bba-reman.com/catalogue/Index.aspx?category=29- Hide quoted text -

- Show quoted text -

What year / engine is it? I do have a set of VX TIS2000 service disks on the laptop at home, not very user friendly but most of the tech.
info is on them. somewhere.

Engine type according to car ID plate = Z10SE/02PP4893
Car on a 53 plate (October)

 

[airsmoothed]

Engine type according to car ID plate = Z10SE/02PP4893

What year / engine is it? I do have a set of VX TIS2000 service disks on the laptop at home, not very user friendly but most of the tech.
info is on them. somewhere.

Engine type according to car ID plate = Z10SE/02PP4893
Car on a 53 plate (October)- Hide quoted text -

- Show quoted text -

Z10SE = 1 litre engine? I didn't think they did one that little? maybe it's Z14 or Z16 , assuming a petrol engine?

 

[Pete (archive)]

Engine type according to car ID plate = Z10SE/02PP4893

What year / engine is it? I do have a set of VX TIS2000 service disks on the laptop at home, not very user friendly but most of the tech.
info is on them. somewhere.

Engine type according to car ID plate = Z10SE/02PP4893
Car on a 53 plate (October)- Hide quoted text -

- Show quoted text -

Z10SE = 1 litre engine? I didn't think they did one that little? maybe it's Z14 or Z16 , assuming a petrol engine?

Yes you are right it is Z16 petrol poor printing my excuse

 

[airsmoothed]

Z10SE = 1 litre engine? I didn't think they did one that little? maybe it's Z14 or Z16 , assuming a petrol engine?

Yes you are right it is Z16 petrol poor printing my excuse

ok dokey, my tis2000 is playing silly buggers, so I'll check my Zafira Haynes book of jokes, that should cover the engine.

 

[Mike (archive)]

Z10SE = 1 litre engine? I didn't think they did one that little? maybe it's Z14 or Z16 , assuming a petrol engine?

Yes you are right it is Z16 petrol poor printing my excuse

ok dokey, my tis2000 is playing silly buggers, so I'll check my Zafira Haynes book of jokes, that should cover the engine.

FWIW. the 'stat on our 1.8 zaf is a thing that comes complete with an alloy housing, so wasnt cheap (an expensive VX part-now theres a surprise!) that bolted to the front of the engine right next to the cambelt cover. Once I removed that silly plastic lid on the engine it wasnt too bad to get off, but a bit fiddley, is all. 15 minute job

Mike

 

[Pete (archive)]

Hi

sorry for the delay in repying my computer has been down this weekend

Just a question when your theromstate was faulty did the light with a car and spanner come on?

pete