Coolant Issue - High Readings

[Craig!]

OK, so first day of TVR ownership may not be going too smoothly... noticed the water temperature is reading high, between 100-115 and flickers between the readings. Is this likely to just be the coolant temp sensor? Also does the same coolant temp sensor that reads on the speedo trigger the cooling fans as they always seem to be running too.

Also is the cap on the coolant a pressure cap, so in theory if it was physically running hot it would have sprayed coolant everywhere?

[rico23]

Craig! said:

OK, so first day of TVR ownership may not be going too smoothly... noticed the water temperature is reading high, between 100-115 and flickers between the readings. Is this likely to just be the coolant temp sensor? Also does the same coolant temp sensor that reads on the speedo trigger the cooling fans as they always seem to be running too.

Also is the cap on the coolant a pressure cap, so in theory if it was physically running hot it would have sprayed coolant everywhere?

Car has two fans which cut in at different temps. They should only be working when the engine is hot - the first should cut in at around 92 degrees on dash display and the second at 96 i think.

If you disconnect the air temp sensor under the airbox this will make the fans run continously so you need to check if this has already been done if there running all the time.

[Craig!]

The dash has just flagged a coolant sensor fault, its reading air temp so I'm guessing thats not been disconnected.

I'm also a little concerned by a small mist of coolant that seems to appear under the bonnet, am I right in thinking that at 115 degrees it would boil over not just mist out? Pictures to follow of the coolant spray.

[rico23]

Craig! said:

The dash has just flagged a coolant sensor fault, its reading air temp so I'm guessing thats not been disconnected.

I'm also a little concerned by a small mist of coolant that seems to appear under the bonnet, am I right in thinking that at 115 degrees it would boil over not just mist out? Pictures to follow of the coolant spray.

Possibly but the car actually has two sensors for the coolant - one is the actual reading and the other just for the dash display. On mine the dash display is 6 degrees higher than the actual water temperature sensor. So if its reading 115 its probably more like 109.

The car has an expansion tank on the right hand side of the engine (viewed from drivers seat).

Does the dash say 'water temp sensor?'

[Zippee]

rico23 said:

The car has an expansion tank on the right hand side of the engine (viewed from drivers seat).

Presumably his car is an 05/06 build then as prior to this they just had the main header tank?
OP - get yourself to your nearest dealer and have them plug the laptop in, that will give a true reading of the coolant temp. It could be the sender but if you're also seeing a mist of coolant I doubt it. Do both fans come on?

[rico23]

Zippee said:

rico23 said:

The car has an expansion tank on the right hand side of the engine (viewed from drivers seat).

Presumably his car is an 05/06 build then as prior to this they just had the main header tank?
OP - get yourself to your nearest dealer and have them plug the laptop in, that will give a true reading of the coolant temp. It could be the sender but if you're also seeing a mist of coolant I doubt it. Do both fans come on?

Mines an '05 and has this. I was unaware prior to this they only had the main header tank.

[Craig!]

Here's some pictures;





Note its the shadow of the tank you see on the bonnet, not coolant.



The dash hasn't said anything all day, however now it has just mentioned a coolant temp sensor fault.

[Zippee]

If that is coolant on the inner wings then you certainly have more than just a dash sender fault. As mentioned before do the fans both come on? If so at what temps according to the dash readings? First should be around 92deg and both around 96deg. Could be something as simple as an airlock or a dodgy thermostat.
You do indeed have the later mod for the expansion tank I see.

[Craig!]

What's the normal oil temp readings? Oil temp stayed low, if there was a physical coolant issue shouldn't the oil temperature also be effected?

[PipeNslippers]

Zippee said:

If that is coolant on the inner wings then you certainly have more than just a dash sender fault. As mentioned before do the fans both come on? If so at what temps according to the dash readings? First should be around 92deg and both around 96deg. Could be something as simple as an airlock or a dodgy thermostat.
You do indeed have the later mod for the expansion tank I see.

I have been told that you should be concerned about any water temperatures reading above 100...

I cannot see the expansion tank mod in the pictures..happy to be corrected?

The first thing you need to look for is any leaking water pipes (and tighten the clips if you find a leak), and then the next step is to bleed the cooling system...

This involved removing the allen key bolts (one at a time) in the metal coolant pipes near the radiator to let any trapped air out..

The second is to remove the water pipe leading to the top of the near side wing and fill the swirl pot tank until water comes out the water pipe you have just disconnected. Then reconnect the water pipe, fill teh swirl pot to the top and then fill the expansion tank to the top(if you have one)

[Craig!]

Just did a bit of investigative work on a warm car and by 97/98 the first fan kicked in and at 99(!?!) the second had come in. When driving home the oil temps didn't really pass 70 odd degrees, surely 70 miles at 100~114 degrees would have blown a pipe or seized the engine.

Maybe theres two faults thats are un-related, but to do with the same system.

[Druid]

Craig

The connectors on the temp sensors are prone to corrosion. Your temp indication must be considered correct even given overreading. Disconnect the cables from the rear temp sensor and I'll bet they are rusty and the increased resistance fools the ecu into thinking all is well. The forward temp sensor may well be indicating actual temps. The other fan connections near the rad may also need cleaning.

I know this from experience!

[Craig!]

Just an update, topped the coolant up a touch, cracked off the bleed screws one has a tiny 'pfft' of air but not much, drove the car and it still flitters between temps, I presume the flickering temps is normal? I can be cruising along and it'll be 98/102/99/101/104/98/107/99 in the short space of time, as in seconds.

Oil temps seem to stay between low 70's to high 70's is this correct?

Am I right in thinking that if there was a major cooling issue that;

a) It wouldn't have made it 70 miles or would be knocking like an old scrapper.
b) A hose would have blown, and I guess there's warning lights?
c) There would be high oil temps to match the coolant.

I'm wondering if the coolant 'spatter' could be a leak from the radiator end tanks?

[darkmark07]

The flickering of temps over that range is definitely not normal, suggest (as others have before me) that it is either a faulty sensor or an air lock.

[RicSpeedSix]

Craig! said:

Just an update, topped the coolant up a touch, cracked off the bleed screws one has a tiny 'pfft' of air but not much, drove the car and it still flitters between temps, I presume the flickering temps is normal? I can be cruising along and it'll be 98/102/99/101/104/98/107/99 in the short space of time, as in seconds.

Oil temps seem to stay between low 70's to high 70's is this correct?

Am I right in thinking that if there was a major cooling issue that;

a) It wouldn't have made it 70 miles or would be knocking like an old scrapper.
b) A hose would have blown, and I guess there's warning lights?
c) There would be high oil temps to match the coolant.

I'm wondering if the coolant 'spatter' could be a leak from the radiator end tanks?

Oil temp sounds fine - I can be certain on that as just had a dodgy oil temp sensor fixed today whilst down at STR8SIX.

Re: coolant - Looking at your pics, you have the swirl tank without the expander. How much did you top up the water in the first place? If you fill above the elbow then you will find that the car will naturally vent coolant until it comes to that level anyway. This is normal behaviour so may not be anything to panic about.

As for your actual coolant temperature, yours does sound high. Mine tends to sit happily around high 80s early 90s when warmed up, even when on track. As others have said, check that your fans are cutting in. You should be able to hear them, but when stationary just pop the bonnet and have a look.

If everything looks ok, then it could be your coolant temp sensor. My oil sensors was reporting a good 10-15 degrees low until it was replaced today. From what I gather from Jason, it's the same type of sensor used for the coolant as well.

Hope that helps.

[Druid]

Also the Coolant Sensor Fault will be flagged when there is a large mismatch between the sensors. So, plug in a laptop and check what the ecu is reading, disconnect the rear sensor and ensure that both fans run by default.

[Craig!]

Further update, took it out again on my private airfield and done a range of speeds between 60mph and 130mph. The oil temp when moving is 69 through to 73 and then in traffic or parked up its at max 83 so I'm guessing there is no major cooling issue.

The coolant sensor is highly erratic, I'm guessing sensor or contacts as mentioned. It eventually flagged up 'Error 128 - Coolant Sensor Fault'

So I'm guessing there's two small faults which happen to be related, the coolant mist is maybe due to the tower been over filled or at worst the end tanks on the radiator are leaking and coolant is getting blown through as dropplets at speed.

I just panic'd when I saw high coolant temperatures mated to a mist of coolant and was thinking the worst.

[darkmark07]

Craig! said:

I just panic'd when I saw high coolant temperatures mated to a mist of coolant and was thinking the worst.

Welcome to the first few months of TVR ownership ;-)

[ben_ek]

if the temp is changing rapidly it's likely that there is air locked in the system. this can be cleared by running the car from cold while it is stationary with the radiator cap off, you will hopefully see/hear some nice big bubbles released, when the bubbles stop turn the engine off, top it up and put the cap back on. this won't be your only issue as previously stated your readings seem high, so you will def need to check the connections to the sensors and/or get the sensors replaced (quite cheap).

[Craig!]

If I run the car from cold with the radiator cap off, after a short while coolant creeps up the tower and over flows... do I allow it to overflow or replace the cap at this point?

The one thing I've always hated is cooling systems, and typical this is the first potential problem.