hughestill

Hi, my GT6 mk3 has been back on the road for around 8 years now and there are a few little scratches/dings etc that I want to get tidied up, but I no longer have the time that I did when I restored it. So, with a heavy heart and a dull anticipatory ache in my wallet, I'm looking to find a good, trustworthy classics restorer in the Tamworth/Lichfield area... Thanks, Hugh

Pete, Yep, turned it to its lowest setting and am now feeling very smug and pleased with myself.... after a few minutes panic and irritation, when I realised I hadn't put a fuse in after I'd finished wiring it in (doh!), everything works perfectly. Got the temp up to the top of the gauge due to lack of fuse, but then after the fuse went in and fan went on, I couldn't believe how quickly it brought the temperature down - almost instantly to about 95C, then left it idling (translation: annoying the neighbours..) for about 30 mins and temperature stabilised at around 80-85C. Very pleased - thanks everyone for the advice along the way. Looking forward to getting stuck in traffic :-) !! Cheers, Hugh

Hi Aidan, I replaced my 82C thermostat with a 75C one so I'm guessing it's opening/closing as per Pete's post above, and doing a good job of modulating the temperature when there is cold air flowing freely. Pete - looks like my fan is actually from a Dolomite, don't know how much difference that would have made in terms of airflow but I'm guessing pretty marginal. I'm in the process of fitting a Revotec fan with an override switch, and there's no room to keep the orignal fan now. Cheers, Hugh

Pete you're right - once I looked at it, I remembered fitting it and it was a pig - very fiddly. If I'd tried to fit it the other way round it wouldn't have. I also checked and it is definitely sucking, not blowing, although the airflow is rubbish - mine is 8 bladed so maybe it's not a GT6 fan at all. Looks more like one stolen from a desk fan to be honest. All that aside, I've taken the car out for a couple of longer runs (20 miles or so still counts as a longer run for me at the moment) and it runs happily at 70-80C, and only gets hotter when it's stationary. Therefore, I shall: (i) Pick up a proper GT6 fan (ii) Fit an electric fan with override switch Then I'll be happy taking the car places where other people might be.. :-) Cheers, Hugh Si

Pete I have a plastic fan but I confess I haven't counted the blades. "More than 2" is all I can tell you at the moment.. I seem to recall it was a bit of an improv/bodge getting it to fit so possibly isn't the right fan, and also it's possible that as part of said improv/bodge it was fitted the wrong way round (do the engine driven fans blow instead of suck if fitted the wrong way round?). Top of my list to check in the morning. Ben, Doug - when I had the block flushed they checked the water pump, thermostat and heater valves, all good apparently. Cheers Hugh

Thanks John - after reading this, I re-read my post and what I should have said was "On returning home, left the car IDLING on the drive for 10 mins". I'm not so worried about the heat while the engine has stopped, it's the potential for overheating in traffic that concerns me - but, I think it looks like an electric fan should do the trick for that. I've been trying to work out what spec fan produces a comparable airflow to that generated by travelling at 40mph but my maths isn't up to it, it would appear..

So, it may just be a case of "I own a GT6".... I'd welcome a bit of a sanity check on the following: Having bypassed the heater matrix with one of those flexi copper tap connectors, I let the car warm up to 190F/(88C on the drive, then took it out for a run. Maintains temperature at around 160F/71C on a 20-30 min run from warm. At higher speed, temp drops even more which makes me think the airflow over the radiator is good, and the core of the radiator is good - does that make sense? On returning home, left the car on the drive for 10 mins (temp just below 160F/71C on arrival), and it heated up over the course of that time to the top of the gauge (230F/110C). I checked all the temperatures around the rad with an infrared heat gun and confirmed alloy thermostat housing temp at 229F, top hose temperature around 215F/102C, bottom hose temperature around 205F/96C. Initially I thought the differential between top and bottom hoses was way too low but then remembered the airflow over the rad was minimal to non-existent. Anyone think that differential is still too low? My final conclusions at present are: - I own a GT6 where cooling is marginal at best. - I need to look at the standard crankshaft fan to make sure it's fitted the correct way round - I need to invest in an electric fan (any recommendations for optimum/best?) - I need to replace the heater matrix (grr..) Anyone think I should be seriously concerned about anything? Cheers, Hugh

Doug, looks like everyone else beat me to it! I have exactly the same as Aidan, dual gauge with capillary temperature sensor.

Hi Pete, Thanks, existing thermostat (the slightly lazy one I replaced) had a jiggle pin, new one didn't but I had drilled the hole before I fitted it. Got my infrared thermometer today - weather and time have run out today but hopefully I'll share a few readings tomorrow..... Cheers, Hugh

Hi John, I've got a mechanical temperature gauge, so if I understand it correctly the voltage stabiliser is eliminated from the equation? Also as per original post, I've cross checked with the self adhesive temperature strips - they obviously don't give a specific reading but indicate if a certain temperature range has been reached. Even allowing for some margin of error I think 230 degrees on the strip and the gauge suggests definite hot running issue. However, all that said, I have ordered an IR temperature gun so I can record more exact readings! Having had the block waterways flushed, and still having a problem, I'm narrowing it down to the following: - blocked heater matrix (looking at that this morning). - radiator issue (would be disappointed as I had it re-cored with an uprated core and pressure tested before rebuild). Couple of questions on this: - will it/should it help if I bypass the heater matrix? I've seen a few threads on various forums suggesting it won't cause any problems, and in some cases resolves an overheating problem, but I can't see how it's any different from just closing the heater valve? - clutching at straws, but is it possible to fit a GT6 head gasket upside down, thus blocking water channels? From what I can see, it's pretty much symmetrical so my feeling is not (I have a non-recessed block). If it IS possible, what other symptoms might I expect to see? Also - how hot is REALLY too hot? When I'm looking at temps in the head/hoses/water pump housing, at what point should I become concerned? Thanks to everyone for their replies and suggestions! Cheers, Hugh

Thanks all, an electric fan is already on my shopping list, so we'll see where today's experiments end up. Pete - you've confused me now. I was under the impression a richer mix would lead to a cooler engine, as the additional fuel in the mix makes the burn temperature lower. I can see why this would be a good thing generally for running in, as it would reduce the power output and protect components, but I'm missing the connection between thermostat opening temp and fuel mix. Thanks Hugh (fully prepped for a chemistry/physics lecture.. :-) )

Thanks Clive. I've just taken the old one out, which was an 82, and I think it may have been seized - I put it in a pan of boiling water and it took about 30 seconds to open, and then did so quite suddenly. Now, while it moves more freely than it used to, it's still very stiff compared to the new 75 degree one I've bought. I'll get the new one in and report back. Thanks again, Hugh

Hi all, My GT6 is running hot - not an unusual cry from the forum I'm aware. Just wondering if anyone can suggest most likely cause? Setup is as follows: ⦁ Newly rebuilt engine (about 350 miles since rebuild) ⦁ Original (but re-cored) GT6 rad ⦁ Radiator & engine shrouds ⦁ Original mechanical fan ⦁ Coolant:water mix 20:80 ⦁ 15lb rad cap ⦁ No front number plate blocking the air flow to the radiator ⦁ Mechanical (capillary) temperature gauge (backed up by Racetech temperature strips on the head) ⦁ Standard thermostat The car seems to be OK while on the move, but if I leave it idling @ around 1000rpm on the drive for 15-20 mins it hits the top of the (mechanical) gauge. I've also verified the temp gauge by using Racetech self adhesive temperature strips on the front of the head, and it suggests temp gets up to 230F (110C). I've no evidence of the coolant boiling, nothing in the catch tank - but then I wouldn't expect it to boil until about 125C with the combination of coolant mix and rad cap. There's no apparent loss of coolant from the system and the oil looks..well..oily, so I'm ruling out HG failure. It's been like this from the moment the engine was started after the rebuild, so it's a constant feature/issue. At the moment, my list of possibles is: - thermostat: was new on installation, and I THINK I checked it before I put it in, but possible failure? - head/block/heater matrix silted up: but, if that's the case, why does it run cooler (between 190F/88C and 212F/100C) when moving? There can't be enough air cooling effect to bring down the temp that significantly, surely? That's about it. Sat here scratching my head, so any suggestions welcome. Thanks, Hugh (I do plan to retest using the self adhesive strips on the thermostat housing, as I'm aware the head is the hottest part of the engine, can anyone advise what is an acceptable temperature range for either/both of those points?)

Wow! I'm not sure where to start, they look fantastic, thank you John. I will PM shortly with my address.

If you were prepared to make some for me that would be fantastic - as long as it wasn't too much trouble. The only problem I have with making them is time - with a 7 year old and a 2.5 year old, I struggle with getting time for much, let alone garage work (hence it's taken me 2 years to get around to this "final job" of the restoration..). However they are both boys so in ten years time I'll have an energetic and enthusiastic project team for something..!