water temp problems.

[Nad-5GTT]

Hello I'm after some advice please. I'll give some info first, I drove the car and the temp was fine around 80° ish then after about 40 miles it jumped to 120° it's maximum reading ( aftermarket gauge ) I immediately pulled over expecting carnage to appear but she was as cool as a cucumber but if you wiggled the spade terminals by the sensor on the water pump the reading dropped. So I binned the spade terminals and got myself a oe terminal plug and soldered that on. My next drive out was in July to the retro show, the temp was fine for about 5 miles then it shot up to 120° and was like that for its 150 mile round trip . Now I've bought a brand new temperature sensor from Mike 16v and the temperature rose to 120° within a few minutes. I've bled the system about 5 times now. I've got an adjustable fan sensor that's fitted after the thermostat obviously and this is kicking the fan in and out like it should. I've stopped the engine and left it for a while had a cup of tea came back and the reading was down to 60°, so I've started the engine and within a minute the reading is at 120° . Any suggestions please

[J8TRO]

I cant offer a solution, but had similar issues with my car. I didn't resolve mine before taking it off the road, but mine will be having a different engine fitted which I hope will rectify my issue.

Can you connect the original dash clocks temp gauge back up and see how that reads? This would eliminate the aftermarket gauge being at fault. I didn't have an aftermarket gauge, but borrowed another set of dash clocks and the reading was the same. At the time a lot of people said mine could have been faulty clocks. This mitigated that.

I replaced the sensor, bled the system numerous times. mine however was over a 5 minute session on track, not 1 minute sat on the drive. Your issue sounds electrical, mine was most definitely mechanical.

Your aftermarket gauge is one thing you haven't changed yet. You could also check it by putting the sensor in boiling water as a check temp.

[Nad-5GTT]

Thanks for the quick reply, I only run aftermarket gauges I've simplified my wiring etc and stripped out the interior so there's not alot or going on there. I have thought about the boiling water test and am just about to do it right after this, I have done this before I replaced the sensor but may as well try again as its easy. I'll post up soon

[Guybrush]

Water's flowing round the system ok? (My water pump went recently, it wasn't leaking... just ceased up. harder to spot).

The top rad hose is getting hot? The radiators getting hot?

Once the cars up to temp, stop the engine detach the lower rad hose and catch the rad water in a bucket, then measure the temperature with an accurate gauge

[Nad-5GTT]

I've just put the sensor into a cup of boiling water and the temp went to 110° I then watched it drop progressively down to 40° before it dropped off the scale, so this means my gauge works and my electrics are in working order guybrush that seems a dangerous idea I haven't got a thermometer either. Might have to invest in one. I really can't see what's going wrong

[Guybrush]

guybrush that seems a dangerous idea

Yeah, chances of burning yourself are mid->high

[TNT ANDY]

Water pump spat its teeth out?

[chris]

Is the water circulateing around

[Alex]

Sounds like a blocked radiator.

[Fordy]

Or thermostat not opening all the way

[Nad-5GTT]

Sounds like a blocked radiator.

when the problem started it was with a copper cored rad and the coolant was clean as a whistle, I've literally just replaced this for an aluminium rad.

[Nad-5GTT]

Or thermostat not opening all the way

I will have to do the boiling water test on this tonight. Thanks

[Nad-5GTT]

Is the water circulateing around

Well all the hoses are getting warm and I checked the rad when it was first started and it became warm on the entry side then switched across to the exit side so I'm guessing that it is. how else would I be able to tell if it's circulating ok, thank you for all the posts peeps.

[Nottswoody]

when the problem started it was with a copper cored rad and the coolant was clean as a whistle, I've literally just replaced this for an aluminium rad.

Did you get that rad from that eBay link? Hope it's not that bud.. Plus I have one for my b18 but haven't used it yet..

[Nad-5GTT]

Water pump spat its teeth out?

It's a fairly new pump, well it's old but has hardly done any miles on it and sounds quiet, but I'm thinking this could be something I need to look at, what do I need to look for

[Nad-5GTT]

Did you get that rad from that eBay link? Hope it's not that bud.. Plus I have one for my b18 but haven't used it yet..

Yes it was from that link Nottswoody, I did thank you but don't panic it's not the rad I know that for a fact.

[Alex]

Take the thermostat out and run it up again to see if it still overheats.

[Guybrush]

is water being returned to the header tank from the top hose?

read my thread : https://www.rtoc.org/boards/showthread.php?t=34961

[Nad-5GTT]

is water being returned to the header tank from the top hose?

read my thread : https://www.rtoc.org/boards/showthread.php?t=34961

You know what I don't think it is I assumed it was just a fail safe pipe to run back into the expansion tank. I think I might need a lesson here. Why would the water not be running through this pipe.

[Guybrush]

I'm still curious about the best was of testing that the water pump is pumping water round..?

With the engine running you should see a steady flow of water returning to the header tank from the small top pipe.

Why would the water not be running through this pipe.

Water pump aint working.

[Nad-5GTT]

Water pump aint working.

I believe your right more pennies. I have just $started the car from cold and it took 3 minutes to reach 120° but in this time I looked in the tank for the flow from the top hose and it was trickling in, then once it had reached that temp I looked in the tank again and it had stopped. I also took the thermostat out and ran it up again and there was no difference. But the thing that's just making me doubt the pump is the rad is getting hit all over which tells me water is being pumped through. But on the other hand there's not much else that could go wrong. Oh and the thermostat just tested fine.

[Alex]

If it's just idling it will only trickle in. Try giving it a good rev, it should increase the flow. It shouldn't stop if the thermostat is open though?

[Nad-5GTT]

Ah this is better news, it's definitely not the rad I've literally just put a brand new one in. I'm confused.

[Nad-5GTT]

Right I've just run her up again, no thermostat in place, cold rad both sides and then they both warmed up so water is running through it which would mean the pump is pushing water round and your right Alex i revved it up a little and the lovely pink coolant came pouring out. Also although my gauge went up to 120° my fan won't kick in till about mid to late 80`s depending on where I've set it too, so it can't be at that temperature. I'm going to strip the pump down at some point,I don't know if something is blocking the water by the sensor. It's really getting me

[michael tierney]

on the off chance if ur guage is electrical??? check that the voltage is steady........around 13.8volts.......if its a purely mechanical guage then check it with sender in kettle.

[Nad-5GTT]

on the off chance if ur guage is electrical??? check that the voltage is steady........around 13.8volts.......if its a purely mechanical guage then check it with sender in kettle.

Ye it's an electrical gauge. I shall get this checked, thank you Michael.

[TNT ANDY]

on the off chance if ur guage is electrical??? check that the voltage is steady........around 13.8volts.......if its a purely mechanical guage then check it with sender in kettle.

Good call

[casper]

When i changed my water pump and temp sensor i put the wires to the sensor the wrong way round.This caused the temp gauge to rise quicker and higher than before.

[Dave Reed]

Ye it's an electrical gauge. I shall get this checked, thank you Michael.

Also what sensor are you using? If it's the standard one then I would think the resistance of the sensor will be different to what the gauge is calibrated to.

[Nad-5GTT]

Also what sensor are you using? If it's the standard one then I would think the resistance of the sensor will be different to what the gauge is calibrated to.

It's a brand new oe sensor, but the old one worked fine going to a Surrey meet then all of a sudden it just jumped 40° then it was a bit hit and miss, hence me buying a new one. The thing is I've kettle tested the sensor and it works fine so it's not the wiring or the gauge. But I will check the voltage, just need a tester now I'm going to have to replace the pump or at least split it apart to see what's going on. It's something small and annoying because I drove back to kent from Santa pod at 30° air temps with the gauge showing 120° and I didn't have any overheating problems.

[Nad-5GTT]

When i changed my water pump and temp sensor i put the wires to the sensor the wrong way round.This caused the temp gauge to rise quicker and higher than before.

I can't put the terminal the wrong way round, but thanks for the reply bud.

[J8TRO]

I can't put the terminal the wrong way round, but thanks for the reply bud.

But could you have soldered your wires to the terminal the wrong way? You saif in an early post that you ditched the spade connectors and soldered a proper terminal in.

Just a thought

[Brigsy]

You need the correct sensor for the gauge if you are using aftermarket gauges.

[Dave Reed]

It's a brand new oe sensor, but the old one worked fine going to a Surrey meet then all of a sudden it just jumped 40° then it was a bit hit and miss, hence me buying a new one. The thing is I've kettle tested the sensor and it works fine so it's not the wiring or the gauge. But I will check the voltage, just need a tester now I'm going to have to replace the pump or at least split it apart to see what's going on. It's something small and annoying because I drove back to kent from Santa pod at 30° air temps with the gauge showing 120° and I didn't have any overheating problems.

Before you go ripping it apart and breaking other stuff (like these cars always do )
I would check with the manufacture of the gauge and see what resistance the senor needs to see to have the correct scaling.. I'm willing to bet that's what your issue is..

[Nad-5GTT]

Before you go ripping it apart and breaking other stuff (like these cars always do )
I would check with the manufacture of the gauge and see what resistance the senor needs to see to have the correct scaling.. I'm willing to bet that's what your issue is..

But if it was this resistance thing why would it work in the just boiled cup of water? And it worked fine before hand? Please don't take it the wrong way I'm curious and want too learn

[Nad-5GTT]

You need the correct sensor for the gauge if you are using aftermarket gauges.

Again I'm asking the same question as I have to Dave, but why would it work ok ie read true then just stop? I'm no electrical engineer hence the questions. And why would the kettle test work. Engine wasn't running for this test but ignition was. But you have reminded me that I do have a sensor that came with it but it's too small for the oe thread thanks to everyone who is coming up with possibilities.

[Nad-5GTT]

But could you have soldered your wires to the terminal the wrong way? You saif in an early post that you ditched the spade connectors and soldered a proper terminal in.

Just a thought

Umm I'm 99% sure it's the right way or was that 50% dam you

[Dave Reed]

But if it was this resistance thing why would it work in the just boiled cup of water? And it worked fine before hand? Please don't take it the wrong way I'm curious and want too learn

It will still work but the scaling will be wrong.. If you have the correct senor measure the resistance on both and I bet its different.

[Nad-5GTT]

It will still work but the scaling will be wrong.. If you have the correct senor measure the resistance on both and I bet its different.

How would I do this Dave?

[Dave Reed]

How would I do this Dave?

http://www.youtube.com/watch?v=wFHWpgHMAvY

[Nad-5GTT]

I could kiss you it never fails to impress me how people on here are so willing to waste there time helping others out with there problems. Thanks Dave, I've always thought I need a multimeter will any type do by that I mean price wise.

[Dave Reed]

I could kiss you it never fails to impress me how people on here are so willing to waste there time helping others out with there problems. Thanks Dave, I've always thought I need a multimeter will any type do by that I mean price wise.

No worries fella. Yeah cheapo ones are fine.. Obviously it may not last, but then you don't tend to use them all that often. Your more than welcome to borrow mine, but you'd probably spend more in petrol getting to mine than a cheapo meter would cost lol.

[Nad-5GTT]

Sweet, ye your right about the cost to collect from you, I think my mpg in my daily is around the high teens at the moment but thanks for the offer. Plus I do like my tools.

[LiamR]

Aren't you near me mate? You can borrow my multimeter

[Nad-5GTT]

Cheers Liam for the offer but there only cheap so I'll just buy one.

[LiamR]

Cheers Liam for the offer but there only cheap so I'll just buy one.

No problem. I have a cheapo one and an expensive one. Guess which one I use most lol.

Good luck with getting it sorted mate.

[Nad-5GTT]

Right all those who said I need to use the sensor that came with the gauge pat yourself on the back I've bought a multimeter today that also came with a temperature probe, so I thought I may as well do a test on each sensor using this probe and linked it to the gauge. Here are the results. Pic 1 is with the gauge sensor and pic 2 is using my old oe sensor. Now that people have mentioned this it makes sense, but what I can't get my head around is why the gauge worked with the oe sensor for about 500 miles then all of a sudden just stopped.

[Dave Reed]

Right all those who said I need to use the sensor that came with the gauge pat yourself on the back I've bought a multimeter today that also came with a temperature probe, so I thought I may as well do a test on each sensor using this probe and linked it to the gauge. Here are the results. Pic 1 is with the gauge sensor and pic 2 is using my old oe sensor. Now that people have mentioned this it makes sense, but what I can't get my head around is why the gauge worked with the oe sensor for about 500 miles then all of a sudden just stopped.

Now tell me how glad you are you didn't rip it all part and still be no closer to solving the issue
I can't answer why it worked other than your old sensor was knackered and it just so happened to show you the correct reading.. It probably was 20yr old..

Re fitting the new sensor remove the blanking plate at the over end of the head and drill n tap it on there..

[Nad-5GTT]

Oh your definitely right there Dave I would have been pretty , ye I've sussed out that location for the new sensor just got to work out what thread I need it's just over 10mm on my digital caliper and I'm going to guess a 1.5 thread.

[Alex]

Glad you got it sorted and if you need to offload the new OE sensor let me know