Bugger! Lambda light and P0116 code

[Hound]

Before I attempt to replace any bits I'd appreciate the opinions of those who are wiser than I!

Since I started driving this car (October) I noticed that the temperature gauge needle didn't sit halfway but at around 4 o'clock, only going to 3 o'clock when the car wasn't moving. I put this down to the lower outside temperature. Fuel economy was 23.3.

Last night the Lambda light came on. The car seemed to drive fine but fuel economy dropped 2mpg, and when I got home and switched off the engine, the radiator fan ran for several minutes. The temperature gauge had also dropped very low.

Turned the ignition on this morning and the fan came on at once. Started the engine, the fan speed increased, then shut off after 15 seconds. It hasn't come on since. I noticed the engine idled higher than normal, though not rough.

OBD2 scan pulled one code: "P0116 - Engine Coolant Temperature Circuit Range/Performance Problem"

I cleared the code, Lambda light disappeared, engine idles at 880 and no fan yet. Antifreeze in expansion tank looks clean and oil hasn't turned to chocolate milk, so hopefully not a blown head gasket!

So my main suspect is the thermostat and its temperature sensor. But if anyone has a deeper insight please chime in.

Lambda sensor was changed in 2010 by the way, and for what it's worth the car (a 1998 C70 T5 GT auto, Motronics 4.4) also has a RICA ECU 310 upgrade.

Thanks in advance!

[Jamest5r]

It just had a hiccup, if it doesn't do it again happy days, old cars and all that

[Hound]

Hope you're right. But I think I will price up the 'stat and sensor. Can't find any record of them ever being changed in the paperwork!

[JamesT5]

I've just ordered an Engine Temperature Sensor and Thermostat for my T5, cost is about £30 plus carriage from Parts For Volvo's. For that money, you might as well change the pair (and the Thermostat seal). Up to you of course.

[stribo]

Had the cold running problem on both our Saffys, just changed the thermostat and problem solved, that having been said, it never brought up an engine light, but they're both pre ME7. When the 'stat went on the S70 (ME7) it stuck shut, so the car overheated, still didn't bring up an EML though.

[JamesT5]

A faulty sensor will also cause poor gas mileage and rough running.

[Hound]

Thanks James, sounds sensible to me especially with winter round the corner.

[JamesT5]

Thanks James, sounds sensible to me especially with winter round the corner.

If you know someone with Vida near you, get them to check for something like this.....

[JamesT5]

Thanks James, sounds sensible to me especially with winter round the corner.

If it helps, my T5 fuel economy is appalling at the moment and my temperature gauge was sitting half way between the far left and the dead-center (operating temperature) lines after a good run up to Aberdare earlier today. I have the fault code stored as shown in the above picture and when I cleared the codes and ran the car the next day, I scanned it again and the code came back. I'm almost certain you've got a similar problem to me.

[Hound]

My 98's fuel economy has stayed pretty much rock steady at 23.3 until this happened last night. (By contrast my '99 gets around 27mpg, it's a 2.5 ME7.) But I always thought the gauge read a bit low when on the move. Engine didn't feel at all rough.

Don't know anyone with Vida but I will see if Vol-FCR tells me anything (I used Torque to get the code). Thanks for the tips James.

Steve, did you get genuine 'stats or decent aftermarkets for your Saffys?

Glad nobody has suggested there's a more sinister or expensive problem!

[stribo]

My 98's fuel economy has stayed pretty much rock steady at 23.3 until this happened last night. (By contrast my '99 gets around 27mpg, it's a 2.5 ME7.) But I always thought the gauge read a bit low when on the move. Engine didn't feel at all rough.

Don't know anyone with Vida but I will see if Vol-FCR tells me anything (I used Torque to get the code). Thanks for the tips James.

Steve, did you get genuine 'stats or decent aftermarkets for your Saffys?

Cheap Eurocarparts ones, they only take 10 minutes to change, so even if they give up in a year, it's not a major issue to change them again, and they're only £2.88 if you order online.

http://www.eurocarparts.com/ecp/c/Vo...a8a9eed&000325

[JamesT5]

£2.88 down from a list price of £22.85! Shows how much of a mark-up there is on these car parts if they can afford to knock 90% off the selling price.

[JamesT5]

My 98's fuel economy has stayed pretty much rock steady at 23.3 until this happened last night. (By contrast my '99 gets around 27mpg, it's a 2.5 ME7.) But I always thought the gauge read a bit low when on the move. Engine didn't feel at all rough.

Don't know anyone with Vida but I will see if Vol-FCR tells me anything (I used Torque to get the code). Thanks for the tips James.

Steve, did you get genuine 'stats or decent aftermarkets for your Saffys?

Glad nobody has suggested there's a more sinister or expensive problem!

I'd advise changing the Thermostat rubber seal as well, the chances are the old one is past its best and for a couple of quid it's not worth skimping.

[Hound]

Blimey, £2.88? Thanks for the heads-up! Comes with gasket too!

Actually £3.72 for the '98. Different part number apparently.

And the temperature sensor is £14.21...

I wouldn't normally touch cheapo parts but as you say it's a comparatively easy job. Plus I assume your Saffys haven't blown up yet, LOL.

[Biff]

I had this problem, turned out I didn't have a stat in my saffy & the temp sensor was goosed. Didn't smell of fuel when I changed it & my mpg went up.

[Hound]

It did occur to me that there may not be a 'stat in there, Mr Biff. But I have a degenerative spine condition so didn't feel inclined to look unless absolutely necessary!

How's Biff Jr doing?

[stribo]

Blimey, £2.88? Thanks for the heads-up! Comes with gasket too!

Actually £3.72 for the '98. Different part number apparently.

And the temperature sensor is £14.21...

I wouldn't normally touch cheapo parts but as you say it's a comparatively easy job. Plus I assume your Saffys haven't blown up yet, LOL.

£2.88 is for ME7, which I thought yours was, £3.72 is for pre ME7. Had no problems with any of them and I've used them on all 3 of our P1 cars.

[Hound]

Steve, it's a '98 with a throttle cable which I thought meant it is M4.4.

[960kg]

DON`t chance cheap parts on the engine wherever they are from reduced price or what!......

Go to Volvo...pay once...fit once = reliable performing motor.

Cheaper than a new engine and using more fuel...

[stribo]

Steve, it's a '98 with a throttle cable which I thought meant it is M4.4.

Sorry mate, yeah yours is the superior pre ME7.