stuart147 Posted March 3, 2012 Share Posted March 3, 2012 I have owned my Caterham for 4 years now and have always worried about the engine temperature. I have covered thousands of miles in it including a trip to France and several other long distance blats over the years. I have a persistent problem with the temperature on the car. If I drive the car normally ( can you drive a Caterham normally?) the temp guage stays at a steady 80ish but the minute I boot the car, the temperature guage lowers to about 40 and does not return to 80 until I return to normal speeds. Could it be the guage? I have changed the sender and have no other issues. The heater works fine and all hoses are getting hot. Should I just enjoy and leave well alone or investigate further? K Series 1.6. Stuart Link to comment Share on other sites More sharing options...
Jason Plato Posted March 3, 2012 Share Posted March 3, 2012 blank off one third of the rad Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted March 3, 2012 Share Posted March 3, 2012 Sounds like big airflow through the rad, which is doing it's job. I run with one third or two thirds of the nosecone opening blanked off at this time of year, with some black closed cell sponge between the inner mesh and the 7 grille. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 3, 2012 Member Share Posted March 3, 2012 Have you checked that the fan isn't on when it shouldn't be? Is the effect related to air temperature? See this thread Jonathan Link to comment Share on other sites More sharing options...
Johnty Lyons Posted March 3, 2012 Share Posted March 3, 2012 What Dave said common problem if outside air temps not absolutly blistering like 2005 in Texas you need to block off 1/3 of rad its being too efficient Link to comment Share on other sites More sharing options...
St Eve Posted March 3, 2012 Share Posted March 3, 2012 I have a similar (but intermittent) problem. I understood it was likely to be air in the system. If the drop in temperature becomes persistent I run the engine from cold to normal operating temperature with the cap off the expansion bottle, and the heater full on. This takes about 10 minutes and usually expels any air. Then all is well until I have to do it again – which is usually a couple of months later. Must fit the bleeding T-piece sometime… Did 96 miles last Thursday (beautiful day!). For part of the journey the temp was 60 degrees, then came up to 80 and stayed there. No serious cause for concern. Air temperature was +14, so I wouldn’t have considered blanking off the radiator. 2007 1600K Roadsport. 7800 miles. Link to comment Share on other sites More sharing options...
stuart147 Posted March 3, 2012 Author Share Posted March 3, 2012 Thanks for the replies. It sounds as if it is just a too efficient radiator. Do other owners run with a part of the radiator blanked off all year or just in the winter. I have had this problem even in France at 35deg all day. Link to comment Share on other sites More sharing options...
CageyH Posted March 4, 2012 Share Posted March 4, 2012 I added a PRRT so I don't have to worry about blanking off the rad. According to the gauge, the temperature sits at a steady "just over 80" degrees. Link to comment Share on other sites More sharing options...
6speedmanual Posted March 4, 2012 Share Posted March 4, 2012 Stuart Is it possible you have no thermostat? Faster water flow with no regulation can also lead to overcooling. Peter Link to comment Share on other sites More sharing options...
diggerman Posted March 4, 2012 Share Posted March 4, 2012 There are two things I have read on Blatchat at regular intervals over the last two years. Drilling holes in thermostats and blanking off areas of radiator I'm my opinion both actions are fundementally wrong. The thermostat is fitted to prevent the majority of engine coolant passing through the rad until the specified working temperature is reached. Typically 80 deg C. If working properly, it will then open allowing coolant in to the radiator. If driven hard it will fully open, if the rad can't keep up with the amount of heat produced then fan will start. So if the stat is working there is no point in blanking part of the rad area as if working temp has not been reached the rad is largely switched off. Equally, if the stat is working, drilling extra/ larger holes in it will only have the effect of slowing the rise to working temp, or worse prevent it from being reached at all. I suspect that many cases of engine temp problems are associated with failed, or partially failed stats. They can have quite short lives. But I can't see any circumstances where drilling the stat or blanking the rad is the right thing to do. Having said all that, air locks really must be avoided as this results in localised hot spots which are the cause of many cylinder head problems. Peter Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted March 4, 2012 Share Posted March 4, 2012 A 3mm hole in the thermostat baseplate is hardly going to allow much flow of cold water through. Does allow air to pass though when filling the system - as long as you position the hole at the top when fitting it ! Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted March 4, 2012 Area Representative Share Posted March 4, 2012 Quoting diggerman: ......if the rad can't keep up with the amount of heat produced then fan will start. Surely the fan is only ever effective when the car is either stopped or traveling very slowly. The fan promotes, maybe, a 30mph draft through about 60% of the radiator. 20mph forward travel is likely to produce similar cooling effect to the fan. Quoting diggerman: I suspect that many cases of engine temp problems are associated with failed, or partially failed stats. I agree. I think Stuart's issue is much more likely to be a 'stat sticking open. Link to comment Share on other sites More sharing options...
Johnty Lyons Posted March 4, 2012 Share Posted March 4, 2012 With defference to a couple of posters above WE are talking about a K here the stat of which unlike 99% of other cars is in the return leg So its mainly affected by ice cold water from bottom of rad The bigger and more efficent the rad the worse the problem also the earlier and later in the season the worse the problem.The only thing keeping the stat open is the by pass cct [which because of its height relevant to rest of water cct I'll agree is prone to Air Locks. What should happen and what actually happens is not always as seems. Experience shows that Ks with race rads can and do suffer from over cooling at certain times. The poor ole stat just doesnt get a chance to stay open as it should.And the engine can suffer from thermal shock as a result don't even start me on Mk 1 Elises they are a blinking nightmare. Sorry Guys Rant over. Link to comment Share on other sites More sharing options...
CharlesElliott Posted March 4, 2012 Share Posted March 4, 2012 What radiator are you running? Link to comment Share on other sites More sharing options...
stuart147 Posted March 4, 2012 Author Share Posted March 4, 2012 There seems to be a lot of possible reasons for this problem. I have had the thermostst changed and it has indeed got the small hole in it to aid bleeding. I also have the famous T piece bleeder fitted. In answer to the last post, it is a bog standard Caterham radiator. Link to comment Share on other sites More sharing options...
Jason Plato Posted March 4, 2012 Share Posted March 4, 2012 the problem is that the cooling system isnt designed very well and the system over cools. Nothing to do with the stat be buggared. One solution is to fit the PRRT system. the other is to blank the rad. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now