Lost Boy Posted January 30, 2011 Share Posted January 30, 2011 I'm hoping someone can help me diagnose a problem with my K series 1.8 supersport. The engine seems to be running colder than usual, the problem started at the back end of the summer last year but the car has been garaged for the winter and I've been out for a blat today and its still an issue! It used to consistently run at 80-90 degrees depending on ambient temperature, on my last trip to the ring it started to run cooler and today its running more like 65 degrees (admitedly its cold outside). I'm concerned it could be doing some damage to the engine, particularly at my next trackday? I'm thinking it could be a number of things, temperature gauge, sender, or the thermostat (sticky?), to be honest that's the extent of my knowledge/expertise and I wondered if there was anyone in the Surrey area who could lend a hand initially with diagnosis? I'm in Fetcham if anyone is local? Thanks in advance Lost Boy Link to comment Share on other sites More sharing options...
Sheds Moderator Posted January 30, 2011 Share Posted January 30, 2011 Almost certainly a sticking thermostat. If you blank off half the rad (gaffer tape is good) and go for a drive, what happens to the temp gauge? If it gets up to 80-90 under normal driving then this points further to a sticking stat. Good news is that it will do no real damage except that the auto choke will stay on longer so *in theory* you get fuel contamination of the oil and accelerated engine wear. Also a cool engine is less efficient, so you ought to fix it. A lot of 7s run without stat though, esp those without heaters. Link to comment Share on other sites More sharing options...
Lost Boy Posted January 30, 2011 Author Share Posted January 30, 2011 Thanks, I'll try that tomorrow, is the stat easy to change? Link to comment Share on other sites More sharing options...
Jetto Posted January 30, 2011 Share Posted January 30, 2011 If you run without a stat (like some race cars do), which gives almost no water temp under normal driving because the coolant is always running through the radiator. Then surely the oil won't heat up sufficiently to cope with going fully hard pace on a track? Or does the oil temperature not rely on water temperature? Link to comment Share on other sites More sharing options...
Sheds Moderator Posted January 30, 2011 Share Posted January 30, 2011 Oil temp is independent of water temp unless you run an oil/water intercooler like a Laminova. Interestingly oil warms up slower than water in an engine in spite of the fact that it has a lower heat capacity and is in the same engine. Of course, in saying that oil temp is independent of water, if cooler water means a cooler engine overall then the oil must be a bit cooler. Racers favour this as they have no problem getting an engine up to temperature. Link to comment Share on other sites More sharing options...
Sheds Moderator Posted January 30, 2011 Share Posted January 30, 2011 Oh and a stat on a K is easy, 3 bolts, clean up, new gasket. TOP TIP search on here for thermostat changing, and watch out for bleeding procedure. IIRC the easiest route is to drill a 2mm hole in the stat so there's no air lock when you bleed the radiator. Finally, a lot of people bleed a K via the heater, or attach a T to the heater hose as this is the highest point unless you jack the front REALLY high. It's been a hardy perennial here for years, so a search will pull up all the best advice. Link to comment Share on other sites More sharing options...
Piers Rendell Posted January 30, 2011 Share Posted January 30, 2011 I had the same issue with the same engine. It turned out to be the sender. Link to comment Share on other sites More sharing options...
Lost Boy Posted January 30, 2011 Author Share Posted January 30, 2011 If I wanted to check the sender, where is it and how can I do it? Link to comment Share on other sites More sharing options...
MADMALC Posted January 30, 2011 Share Posted January 30, 2011 'Oh and a stat on a K is easy, 3 bolts, clean up, new gasket.' Not if you have a dry sump and heater it ain't. Absolute b-----d. S7MAD Link to comment Share on other sites More sharing options...
Lost Boy Posted January 30, 2011 Author Share Posted January 30, 2011 wet sump, but I do have a heater! Link to comment Share on other sites More sharing options...
CageyH Posted January 30, 2011 Share Posted January 30, 2011 With a dry sump, it's one bolt and pull the assembly out. Just did this when fitting my PRRT. Was not difficult, even with Jenveys in the way. My money is on the brass coloured sender in the water rail, just above the exhaust primaries. To make sure it is not a sticky stat, let it idle until the cooling fan kicks in. While it is doing this, check that all the pipes heat up. The lower radiator exit pipe should take longest, but will get warm when the stat opens. If it does not get warm, you either have an airlock or a dodgy stat. Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted January 30, 2011 Share Posted January 30, 2011 Sender for gauge is the one with a single wire on the water rail above the exhaust primaries ... Towards the rear of the engine. Link to comment Share on other sites More sharing options...
CageyH Posted January 31, 2011 Share Posted January 31, 2011 That will be the brass coloured one then Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Jason Plato Posted January 31, 2011 Share Posted January 31, 2011 most people block up 1/3 of the radiator at ambient temps below about 15C. The radiator over cools otherwise and temps deisplayed in the region of 55 > 65C are common. if the water temp rises to 85/90 at idle and then drops when on the move this will be the problem. If it never gets above 65C then you should start investigating elsewhere. here is my Duratec R .... C7 TOP Taffia joint AO with Al Link to comment Share on other sites More sharing options...
Doug Posted January 31, 2011 Share Posted January 31, 2011 I had exactly the same problem with my Zetec and the solution was a new thermostat. Modern thermostats are often made in China and the quality is not particularly good. I'm now on my third in 9 years! 'Have you any idea what it's like to have the wind rushing through your hair!' (Quote:Sq Cdr the Lord Flashheart) Link to comment Share on other sites More sharing options...
Stef Posted January 31, 2011 Share Posted January 31, 2011 I have exactly the same problem on my 2007 car that has only done 2000miles, caterham changed the sensor when I bought the car and have just told me that the k-series is an engine that always runs cool and that with current air temps it will always do that. It definitely comes up to 80-85 when idling and then the fan kicks in. Which to me implys that everything is indeed working and it is just due to the cold air temp. I have never driven it in hot weather so nothing to compare it too. Hadn't thought about blocking some of the radiator off, I'll give that a try (once the salt dissappears!) Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted January 31, 2011 Share Posted January 31, 2011 At this time of year, water temperature of 50-60C is not unusual, unless you blank off part of the radiator. I use a bit of black closed cell foam rubber sheet, and slide it in between the 7 grille and the mesh grille. I have two bits ... one does 1/3 of the opening, the other does another 1/3. I fit one or both ...leaving a vertical band clear in the middle. Link to comment Share on other sites More sharing options...
Stef Posted January 31, 2011 Share Posted January 31, 2011 where do you get 'closed cell foam rubber sheet from? Cheers Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted January 31, 2011 Share Posted January 31, 2011 My rubber and gasket supplier (but in previous job, so lost the contact). It is heat proof too (well, proof enough to lag the Apollo tank too), so multi-purpose. A job for Google or Yellow Pages ! Link to comment Share on other sites More sharing options...
Jason Plato Posted January 31, 2011 Share Posted January 31, 2011 plastic sheet used for pallet protector does it for me - and it's black look on the stock pallets in the b&q etc here is my Duratec R .... C7 TOP Taffia joint AO with Al Link to comment Share on other sites More sharing options...
Jason Plato Posted January 31, 2011 Share Posted January 31, 2011 or card or duct tape or kitchen foil doubled up the list is endless here is my Duratec R .... C7 TOP Taffia joint AO with Al Link to comment Share on other sites More sharing options...
CaterBram Posted January 31, 2011 Share Posted January 31, 2011 Ummm got to say I chuckled with this one, been out for the first couple of times in the zetec, a rock solid 92 degree C (just where it's supposed to be), just starting to open the Thermostat so doing it's job spot on. Certanley an eye opener after the X/Flow, i've pinched idea's from the dark side to put in a cooling circuit which is not overcooled. so regardless of external temperature the engine will come up to running temperature and hold there. -----Q469 WET, 1990 Long Cockpit in Ali except for the red bits. Class 2 150 BHP Zetec. With a Dual Drive :-)CaterBram on Facebook Edited by - CaterBram Jnr on 31 Jan 2011 20:22:59 Link to comment Share on other sites More sharing options...
CageyH Posted January 31, 2011 Share Posted January 31, 2011 A PRRT will fix this, but will cost about £60 to install. Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
CageyH Posted January 31, 2011 Share Posted January 31, 2011 A PRRT will fix this, but will cost about £60 to install. Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
CageyH Posted January 31, 2011 Share Posted January 31, 2011 Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
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