Major over-heat and fans not working
Discussion
Took the car for a long drive yesterday, all fine, after we stopped for petrol we started off again and noticed the temperature gauge climbing past 90 degrees, then hit the end stop.
Luckily we were back close to home and as we pulled into the drive water started to gush out underneath, we heard the water boiling, lifted the bonnet and let it cool down.
Water was coming out around the bottom of the header tank, we restarted and it looks like the fans aren’t working, I’m just going out to check now.
What I'm worried about is could this cause any damage to the engine? and where do I start looking to check the fans?
Thanks,
Griff.
Luckily we were back close to home and as we pulled into the drive water started to gush out underneath, we heard the water boiling, lifted the bonnet and let it cool down.
Water was coming out around the bottom of the header tank, we restarted and it looks like the fans aren’t working, I’m just going out to check now.
What I'm worried about is could this cause any damage to the engine? and where do I start looking to check the fans?
Thanks,
Griff.
If the gauge hit the end stop as in the top end stop then yes it’s more than likely to cause engine damage.
Of course you may well be lucky and and not caused catastrophic failure but you might have caused head gasket failure or worse.
More by luck than judgement you might have just caused extreme water pressure thats just boiled over and out of the expansion tank, that loss of water now requires the cooling system to be re filled and bled to remove air or it will happen again almost instantly.
At this point you would be well advised to check the oil level and wether or not it’s been contaminated with coolant.
Get it recovered to a decent garage that understand TVR cars.
I’m stating the obvious now but you would have been well advised to stop before the gauge went so high and recovered so the possible damage could have been limited to why it over heated in the first place.
Luckily for you the engines are quite hardy so you may have got away with it but I’d not drive it until I’d determined wether water is now in the oil and visa versa as that will indeed cause a very expensive repair.
Of course you may well be lucky and and not caused catastrophic failure but you might have caused head gasket failure or worse.
More by luck than judgement you might have just caused extreme water pressure thats just boiled over and out of the expansion tank, that loss of water now requires the cooling system to be re filled and bled to remove air or it will happen again almost instantly.
At this point you would be well advised to check the oil level and wether or not it’s been contaminated with coolant.
Get it recovered to a decent garage that understand TVR cars.
I’m stating the obvious now but you would have been well advised to stop before the gauge went so high and recovered so the possible damage could have been limited to why it over heated in the first place.
Luckily for you the engines are quite hardy so you may have got away with it but I’d not drive it until I’d determined wether water is now in the oil and visa versa as that will indeed cause a very expensive repair.
Sorry to hear of your troubles. Similar thing happened to me last year and no damage was caused. It turned out to be a corroded connection for the fan connector. Disconnect the fan and check the contacts are good.
I doubt you will have done any damage as you turned off the engine quickly, the cooling system has boiled over and released the heat to prevent the engine getting too hot. Remember the temperature gauge reads the water temperature, not the oil temperature. No harm in getting it checked out by a professional though for peace of mind.
Andrew.
I doubt you will have done any damage as you turned off the engine quickly, the cooling system has boiled over and released the heat to prevent the engine getting too hot. Remember the temperature gauge reads the water temperature, not the oil temperature. No harm in getting it checked out by a professional though for peace of mind.
Andrew.
Simon_GH said:
5.0ltr said:
Easy stuff first, Fan relay then otter switch, hope no further damage.
I think the fuse is a weak point too - especially if the fan is working hard and not running as freely as it should. (So, in theory if one fuse went at least one worked). My otter switch was usually the culprit (and I always kept two small needles in the tool kit to by pass the switch to fans always on
)2 sMoKiN bArReLs said:
Don't know if Griffith is different, but on my later Chimaera the fans were on two separate fuses. One was on the same as the horn!
(So, in theory if one fuse went at least one worked). My otter switch was usually the culprit (and I always kept two small needles in the tool kit to by pass the switch to fans always on)
My emergency fix , is a piece of metal wire between the contacts to complete the circuit (So, in theory if one fuse went at least one worked). My otter switch was usually the culprit (and I always kept two small needles in the tool kit to by pass the switch to fans always on
)
Help Needed for Newbie
I have just bought a 500 griff (2000) I have been advised to fit an override switch but am uncertain about the following
1) Where to take the live feed from for the switch
2) Where to mount the switch
3) Where to situate the relay (Im assuming this is needed) + what power rating for the relay
4) Where to pick up a switch earth
5) What's the best way to piggyback the otter switch or do you wire straight to the fan motors ( one or both??)
6) Is it usual to use an illuminated switch so you know that you have left it on
Sorry to ask so many idiot questions but I bet lots of you have done this and I hope that I won't make too may avoidable mistakes.
Apologies if this is answered elsewhere on this forum
I have just bought a 500 griff (2000) I have been advised to fit an override switch but am uncertain about the following
1) Where to take the live feed from for the switch
2) Where to mount the switch
3) Where to situate the relay (Im assuming this is needed) + what power rating for the relay
4) Where to pick up a switch earth
5) What's the best way to piggyback the otter switch or do you wire straight to the fan motors ( one or both??)
6) Is it usual to use an illuminated switch so you know that you have left it on
Sorry to ask so many idiot questions but I bet lots of you have done this and I hope that I won't make too may avoidable mistakes.
Apologies if this is answered elsewhere on this forum
Not TVR specific but the way I have done it before:
1) Where to take the live feed from for the switch? Direct from the battery with an in line 30A fuse.
2) Where to mount the switch? Under the bonnet, use something water proof and heavy duty like a battery isolator.
3) Where to situate the relay (I'm assuming this is needed) + what power rating for the relay? I never used a relay as I used a thick wire. Relays are to remove the need for high ampage wiring to be routed through the under dash areas and carpets where shorts can cause fires. This is an emergency by pass.
4) Where to pick up a switch earth? Near the fans to the body on a steel car, the nearest earth post for the engine or loom to the chassis will suffice.
5) What's the best way to piggyback the otter switch or do you wire straight to the fan motors ( one or both??) I just go direct with a heavy in line switch, it's an emergency measure.
6) Is it usual to use an illuminated switch so you know that you have left it on? 2 giant fans running at full chat that you had to pop the bonnet to activate that won't run off until you do... You'll remember.
1) Where to take the live feed from for the switch? Direct from the battery with an in line 30A fuse.
2) Where to mount the switch? Under the bonnet, use something water proof and heavy duty like a battery isolator.
3) Where to situate the relay (I'm assuming this is needed) + what power rating for the relay? I never used a relay as I used a thick wire. Relays are to remove the need for high ampage wiring to be routed through the under dash areas and carpets where shorts can cause fires. This is an emergency by pass.
4) Where to pick up a switch earth? Near the fans to the body on a steel car, the nearest earth post for the engine or loom to the chassis will suffice.
5) What's the best way to piggyback the otter switch or do you wire straight to the fan motors ( one or both??) I just go direct with a heavy in line switch, it's an emergency measure.
6) Is it usual to use an illuminated switch so you know that you have left it on? 2 giant fans running at full chat that you had to pop the bonnet to activate that won't run off until you do... You'll remember.
Hmm, yes lots of people have done this but I’ve never considered it necessary.
Otto switches can fail but putting a new one in should resolve that for years.
The Ecu detects water temps and turns fans on at 92 degrees and off again at around 85-88 so keeping the engine at its best operating temperature.
The only time you would need a manual override would be if Otto switch failed so useful then but given a good service record unlikely to happen.
If fans come on and do not go off again your either living in a very hot country, sat in traffic on a warm day or you have a failing cooling system.
The engine bay does get hot but the cooling system is designed to cope with that and thus why I don’t think manual overrides serve a useful purpose other than if your Otto switch fails.
Often people are fooled into thinking the cars getting overly hot because the temp gauge rises which is more a problem with resistance.
The way to be sure is by either plugging in Rovergauge which detects the actual water temp via the Ecu sender which is better situated and more accurate and or listening to the fans. If they are going off that shows the water temp is within operating spec.
By all means fit an override but if your system is working correctly you’ll never need to use it.
I often wonder what’s really wrong with a car fitted with such things
Otto switches can fail but putting a new one in should resolve that for years.
The Ecu detects water temps and turns fans on at 92 degrees and off again at around 85-88 so keeping the engine at its best operating temperature.
The only time you would need a manual override would be if Otto switch failed so useful then but given a good service record unlikely to happen.
If fans come on and do not go off again your either living in a very hot country, sat in traffic on a warm day or you have a failing cooling system.
The engine bay does get hot but the cooling system is designed to cope with that and thus why I don’t think manual overrides serve a useful purpose other than if your Otto switch fails.
Often people are fooled into thinking the cars getting overly hot because the temp gauge rises which is more a problem with resistance.
The way to be sure is by either plugging in Rovergauge which detects the actual water temp via the Ecu sender which is better situated and more accurate and or listening to the fans. If they are going off that shows the water temp is within operating spec.
By all means fit an override but if your system is working correctly you’ll never need to use it.
I often wonder what’s really wrong with a car fitted with such things
BritishTvr450 said:
I often wonder what’s really wrong with a car fitted with such things
My 635CSi was running a big cam and quite a rough and ready power chip and was not in the best of health when I started turning into (what was in my head) a road going Group A car. Manual with an LSD. Oh to be 23 and have £1000 E24's available again.
It probably would have been faster if I had just sorted it's underlying problems out.
Stick Legs said:
My 635CSi was running a big cam and quite a rough and ready power chip and was not in the best of health when I started turning into (what was in my head) a road going Group A car. Manual with an LSD.
Oh to be 23 and have £1000 E24's available again.
It probably would have been faster if I had just sorted it's underlying problems out.
Oh to be 23 and have £1000 E24's available again.
It probably would have been faster if I had just sorted it's underlying problems out.
The good old days of rough and ready power chips for less than the cost of a good air filter.
Group A another fantastic period, don’t blame ya for feeling the nuts at 24 with those mods.
You’ll feel about 18 if you buy a fast TVR
BritishTvr450 said:
The Ecu detects water temps and turns fans on at 92 degrees and off again at around 85-88 so keeping the engine at its best operating temperature.
Sorry, this is incorrect, the ECU does get a temp signal but the ECU doesn’t not control the fans. On a 1996 Griff 500:
The ECU gets a temp signal from its own sensor,
The temp gauge gets a signal also form its own sensor,
The fans are turned on and off by the otter switch driving a relay in the fuse box only.
There is a better position on the engine for the temp gauge sensor which makes it more accurate but you need to put a different sensor in.
As for a manual bypass, I just ran 2 cables from the otter switch to a switch inserted into the column that bypass the otter switch.
Alternatively you could do what’s previously said and insert an emergency supply to run the fans.
It’s been a while but there’s a pink and green wire in the loom near the ECU that’s the signal out to the relay to switch the fans on IIRC. Splice a cable into that, run to a little round rocker switch you can mount on the lower steering column near the height adjuster lever, and run the other switch terminal to earth.
ETA I did it on two Griffs and always used to flick it on at the first sign of traffic. Did I need it? Not sure, but neither overheated.
ETA I did it on two Griffs and always used to flick it on at the first sign of traffic. Did I need it? Not sure, but neither overheated.
Simplest method really without too much faffing for a fan override is to run a 2 core cable back from the otter switch to a dash switch somewhere, you can utilise the dash light off button if the griff has one as this rarely gets used.
Obviously you connect the 2 wires together when you disconnect it to enable the dash lights to work.
If nothing it's a way of manually testing the fans are working.
Obviously you connect the 2 wires together when you disconnect it to enable the dash lights to work.
If nothing it's a way of manually testing the fans are working.
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