Jump to content
paime

Running cool or wonky temperature gauge?

Recommended Posts

As the weather starts to turn up here in the frozen north i'm noticing my TD5 is taking longer to get up to temperature. It's always run a little cool but the needle is barely moving on a 20 minute commute through town. On a longer run i can get it up to temp but if i'm on the motorway then i can only get about 1/5 up the temp scale. The strange thing is that whenever i press the accelerator the needle dips slightly so i'm wondering if the gauge might be the issue. I've checked for the usual head gasket failure signs and there's nothing to note and i've also changed the thermostat about 6 months ago so i'm ruling those two out. No obvious leaks in the system and it holds coolant just fine. Is it time for a radiator muff or should i be looking at that gauge a bit more?

 

Share this post


Link to post
Share on other sites

Get yourself an IR gun, very handy for this sort of thing, just point it at the temperature sender on the engine to confirm whether it is reading properly.

Unless the stat was a good make/genuine I would be suspecting that, as cheap copies are very poor, and can fail in 6 months very often, and the symptoms you state are classic thermostat.

No affiliation, but there are thousands of these on ebay: 

https://www.ebay.co.uk/itm/LASER-INFRARED-IR-NON-CONTACT-GUN-DIGITAL-TEMPERATURE-TEST-METER-THERMOMETER/122512014040?hash=item1c8648fad8:g:~MwAAOSwAPVZFC4U:rk:1:pf:0

Share this post


Link to post
Share on other sites

Cheers Bowie. What sort of running temps should i be seeing? The gauge is an original from what i can tell and can't see any fiddling with any of the wiring behind it either. It's all very strange!

Share this post


Link to post
Share on other sites

Modern turbo-Diesels run hot - it improves efficiency, prolongs engine life and reduces emissions. Temperatures in excess of 100C in the head are quite common (thats also one of the reasons why you need to have the right coolant concentration - the Glycol raises the boiling-point significantly). I'd be aiming for 100C as a 'good' exit-temperature of coolant from the head.

My TD5 does take ages to warm-up though: starting up after an overnight 'cold soak' in frosty weather the needle doesn't move off the stop for the first 3 or 4 miles - it's been like that from new. And in similarly-cold weather if you hit stop-start traffic when the outside-temperature's zero and you've got the heater going full-blast the needle soon sags back into the blue because the heater's sucking more heat out of the coolant than the engine generates at idle.

If I were you I'd be checking your thermostat, and also the condition of the engine-to-earth/battery cable, as corrosion here could generate 'odd' readings. But also remember that the TD5 temperature-gauge is actually driven from the ECU, using data from the injection's Coolant Temperature Sensor - so it could be worth getting a code-reading done in case you have an undrlying issue with the CTS or its wiring.

Share this post


Link to post
Share on other sites

its also worth noting that the td5 temp gauge is controlled by the ecu, not the sender, if you have a bad earth at the ecu this can effect the gauges accuracy in regards to the temperature,

Share this post


Link to post
Share on other sites

but a td5 temp gauge will work if the wire from sender goes direct to the gauge, thats how mine is connected.

  • Like 1

Share this post


Link to post
Share on other sites

Cheers guys. I've suffered from a bad earth from the ECU in the past so i'll start there. Is it worth getting a radiator muff for it anyway as we move into winter?

Share this post


Link to post
Share on other sites

Depends where you live, but in the UK, no.

Share this post


Link to post
Share on other sites

its also worth noting that you can use a thermostat from a k series freelander that's available in 3 flavours which allows you to alter the warm up characteristics, I currently have a black thermostat fitted which is fully opened at 82c rather than the standard 88c

Share this post


Link to post
Share on other sites

Surely opening at 82c instead of 88c would make warm up of the cab even worse, since coolant circulates through the heater whether the t'stat is open or closed?  Or have I got it backwards?

Mike

Share this post


Link to post
Share on other sites

The gauge problem is probably an earth.

The Td5 thermostat opens about 82 and is fully open about 96, so 88-89 would probably be an average running temperature.

2 hours ago, Troll Hunter said:

Surely opening at 82c instead of 88c would make warm up of the cab even worse, since coolant circulates through the heater whether the t'stat is open or closed?  Or have I got it backwards? 

Mike 

Yes coolant flows through the heater matrix all the time and when the RPM is above 1500 the bypass valve opens to prevent pressurising it too much. So driving at RPMs below this will force all the coolant through the heater, though wouldn't create as much heat, so who knows how you heat it up the quickest.

This thread is relevant:

 

Share this post


Link to post
Share on other sites
On 11/28/2018 at 3:27 PM, Troll Hunter said:

Surely opening at 82c instead of 88c would make warm up of the cab even worse, since coolant circulates through the heater whether the t'stat is open or closed?  Or have I got it backwards?

I'd think so - and the 88deg stat only fully opens at 92deg according to the RAVE manual :ph34r:

Share this post


Link to post
Share on other sites

Hi 

There are lots of potential problems with the earthing behind the instruments. One day climbing to the top of Rannoch Moor from Glen Coe the temp went into the red, I pulled off in panic and turned off the headights... and the needle went back to normal.  Lights on needle up. the TD5 110 was not obviously hot.  Problem went away after a general clean up of earthing points on the bulkhead.

 

Share this post


Link to post
Share on other sites

I'm going to give the earth a good going over this weekend and hope that it helps. Interestingly enough my brother's TD5 has also been struggling to come up to temp recently so i'm wondering if it's just the weather. It's been -5C these past couple of days and this morning it was a balmy +6C and she heated up no bother. Also planning on giving my heater matrix a bit of TLC so we'll see how that goes. I found a couple of guides on here and nobody has been particularly enthusiastic about the task!

Share this post


Link to post
Share on other sites

The heater matrix is not a difficult job to do paime, 2 spanners out of 5. Being methodical and stopping air getting around the matrix is the key.

Mo

Share this post


Link to post
Share on other sites
43 minutes ago, Mo Murphy said:

The heater matrix is not a difficult job to do paime, 2 spanners out of 5. Being methodical and stopping air getting around the matrix is the key.

Mo

It seems like a therapeutic job once the matrix is out so hopefully it won't take too long and i won't lose any knuckles in the process.

Share this post


Link to post
Share on other sites

A bit of an update on this one. Matrix has been changed (some knuckle skin was lost along the way, Mo!) and thermostat has also been swapped over. I did the thermostat when i was hungover and accidentally left the water pump hose rubbing off a pulley so ruptured the hose. I then over-tightened the bleed screw and snapped it off. Long story short, i have a new thermostat, new matrix, 2 new hoses and she's still taking an age to heat up!! Is there anything else i should check before buying a rad muff? The viscous fan appears to be working as it should.

The temp gauge is a separate issue and i've noticed that if i put the handbrake on the needle moves up slightly, it's all very bizarre. I also have a temperamental ABS light and the 3 amigos also often appear. Any suggestions?

Share this post


Link to post
Share on other sites
29 minutes ago, paime said:

The temp gauge is a separate issue and i've noticed that if i put the handbrake on the needle moves up slightly, it's all very bizarre. I also have a temperamental ABS light and the 3 amigos also often appear. Any suggestions?

Check  and clean your battery to chassis to engine ground strap, it sounds like you have a bad vehicle earth somewhere causing all sorts of issues, sort this before you spend any more money chasing red herrings.

Share this post


Link to post
Share on other sites
23 minutes ago, Bowie69 said:

Check  and clean your battery to chassis to engine ground strap, it sounds like you have a bad vehicle earth somewhere causing all sorts of issues, sort this before you spend any more money chasing red herrings.

Will give it a bash and see if it helps. Are there any other earth points i should be looking at apart from the main battery to chassis strap?

Share this post


Link to post
Share on other sites

Yes, on the bulkhead near the clutch master cylinder, I think it is a bit hidden behind something on TD5s, so you may need a torch to go on a hunt.

Share this post


Link to post
Share on other sites

Earth point under drivers seat often a problem for the start relay, but worth a clean I'd say. - Farther in laws Td5 I noticed the furl gauge twitches when you rev'd the engine, cleaning that earth point seemed to sort that.

Share this post


Link to post
Share on other sites

Thanks guys, i'll have a crawl around over the weekend and do some tidying up.

Re the slow heating, is there any merit in either removing the viscous fan or installing an electric fan set? A rad muff at £30 is the cheaper option but i'd be worried my intercooler isn't getting the air flow it needs.

Share this post


Link to post
Share on other sites
6 hours ago, paime said:

A bit of an update on this one. Matrix has been changed (some knuckle skin was lost along the way, Mo!) and thermostat has also been swapped over. I did the thermostat when i was hungover and accidentally left the water pump hose rubbing off a pulley so ruptured the hose. I then over-tightened the bleed screw and snapped it off. Long story short, i have a new thermostat, new matrix, 2 new hoses and she's still taking an age to heat up!! Is there anything else i should check before buying a rad muff? The viscous fan appears to be working as it should.

The temp gauge is a separate issue and i've noticed that if i put the handbrake on the needle moves up slightly, it's all very bizarre. I also have a temperamental ABS light and the 3 amigos also often appear. Any suggestions?

ive ran many an additional earth from the ECU tray to the battery negative on TD5's for the issue with the gauges doing odd things,

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy