Dunsfold Dave Posted May 28, 2006 Share Posted May 28, 2006 I've had the car almost two years and it has just started overheating, according to the stack dash. I've tested the system on my drive and it runs up to 86deg fan cuts in brings it down to approx 84 and then cuts out. Thats fine everything working, then why does it keep going to 100deg plus when I'm travelling slowly in traffic. The water pump is working there is plenty of water in the expansion tank etc. It never used to do this. Ive been advised that I should fit an ECU fan control and this would bring the fan in at approx 65deg. THis would mean it would probably take longer to reach overheating levels but would it solve the problem? Its a R400 and do they always suffer from this and should I just fit the Ecu control switch, Larger rad and a larger fan? Its just strange that I've never had the problem before I have also overfilled the car with oil but it does not seem to be filling my oil catch tank from the breather. Is there something that would cause this? When the car overheats say 105deg!!! the oil pressure drops at idle to 5 psi accordingly. None of the problems appear to affect the smooth running of the engine, no misfires or lumpy tickover or hunting etc. Is it possible that the stackdash needs re-setting in some way? I do not want to cause serious damage to the engine and I'm no mechanic but some advise from any of you in the know would be helpful. DD Link to comment Share on other sites More sharing options...
Tom_C Posted May 28, 2006 Share Posted May 28, 2006 Is it oil or water temp that is getting high? I thought mine was overheating, but it was oil I was checking, not water. I've been told that an oil overfill leads to hot oil cos the crank thrashes in the oil in the sump. Unless you have a DS system of course. Cheers Tom FH54WLX - only the car supports ManU, honest! see here - UPDATED Link to comment Share on other sites More sharing options...
Myles Posted May 28, 2006 Share Posted May 28, 2006 Well - for starters - on your drive, you've got clean air for the fan to suck. In traffic, you're quite likely sucking straight from some tintop exhaust. It does make a difference... I'm slightly suspicious about the cut in at 86, cut out at 84 - it's usually quite a bit more of an overlap (my R500 switch cuts in at 80 and cuts out at about 75ish). 65 deg C is too low for the fan to cut in. It's way below even the coolest stat that anyone regularly uses (74 deg C - the R500 spec). It is entirely possible that your stat is on the way out and is (partially) sticking closed. Dunno about the oil-level. Received-wisdom states that DS systems will find their own level... Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
Dunsfold Dave Posted May 29, 2006 Author Share Posted May 29, 2006 Tom - The water temp is hot and as it rises the oil prerssure drops. I do have a dry sump. Myles - Thought I'd drive to work this morning in it. No problem but no real traffic to speak of. Through town my water temp was 87-90deg. What oil pressure when hot does your R500 run at idle. This morning mine was between 12 to 16psi whilst waiting at lights is this normal or rather low. If its overfilled should the pressure read high? DD Link to comment Share on other sites More sharing options...
mav Posted May 29, 2006 Share Posted May 29, 2006 16psi (about 1 bar) is on the low side. I'd expcet something more like 32-40 (2 - 2.5 bar) psi at hot tickover. Link to comment Share on other sites More sharing options...
oldbutnotslow Posted May 29, 2006 Share Posted May 29, 2006 Another thread that I agree with Myles on! There is something wrong and as the car has run satisfactorily before then you need to treat the cause not the symptoms. How recently has this started to manifest itself? Has it been gradual or sudden? If you can reset the Stack then that’s the first thing that I would do. A manual fan override switch is always a good thing to have fitted. If you click on the link below there is a wiring diagram curtsey of Chris W. Why have you over filled with oil when this often a cause of over heating? I would get the oil level down to the correct level for starters If no joy with the Stack reset start to look at other things. Cooling is probably the cause of most over heating problems and stat failure the bulk of these. Replace the stat as a matter of course. Even if it’s not this, the cost is minimal and you will be fairly sure that you can cross this off the list. Whilst you are doing this remove the rad and back flush it to make sure that it’s clear. Also connect a hosepipe and flush the block from the water rail and the heater pipe work If you have one. How do you know that the water pump is working? Have you tested the system for flow? Water in the expansion tank is not an indication that the pump works merely that there is fluid in the system. Water Pump removal whilst simple is a fag because of the other bits that you need to remove to get at it! A seizure is the normal WP failure and is preceded by loud screeching that alters with engine speed. I guess that you would have mentioned this if this had been the case so I would go back to the stat I still suspect the instrumentation readings though! Edited to say that after 25 mins thrashing around a track my car has an OP of around 24 to 25 psi at idle Grant Taylor OBNS Motorsport 😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here Edited by - oldbutnotslow on 29 May 2006 08:57:45 Link to comment Share on other sites More sharing options...
mav Posted May 29, 2006 Share Posted May 29, 2006 Edited to say that after 25 mins on track my car has an OP of around 24 to 25 degrees Eh? Link to comment Share on other sites More sharing options...
oldbutnotslow Posted May 29, 2006 Share Posted May 29, 2006 OK finger to brain link trouble. Now corrected Grant Taylor OBNS Motorsport 😬 183 BHP of Black and 'Stone Chip' excitement. 😬 here Link to comment Share on other sites More sharing options...
Dunsfold Dave Posted May 29, 2006 Author Share Posted May 29, 2006 Thanks for you help. I have over filled with oil out of an inane inability to read the stupid DS dipsick clearly, I just thought it found the correct level by dumping oil into the catch tank. Being thick I had no idea that overfilling with oil causes over heating. I'll take your advise Grant and change the sender and flush through. Do you know how to reset the stack dash? Link to comment Share on other sites More sharing options...
F355GTS Posted May 29, 2006 Share Posted May 29, 2006 Dave it's dry sumped isn't it? ps I've some spare stack senders here in Reading if you want to try one of those Mark Link to comment Share on other sites More sharing options...
Mark w Posted May 29, 2006 Share Posted May 29, 2006 Dave My R400 oil pressure sits at about 23 to 25 PSI at idle when the oil is hot. 5psi doesnt seem right. My temperatures are different to those you state but that is because my car has a 82 degree stat , large rad and large fan with manual overide.If you still have the 88 degree stat which the road cars were fitted with from the factory i wouldnt be surprised to see the temp. go up as high as the mid 90 s in traffic but even the small standard fan should be able to arrest any further rise. As suggested above i would start with the stat , and then change the oil presure sender ( or borrow one and try as they are not cheap) As for the oil level mine seems to take loads of oil but does eventually blow some out into the catch tank , just keep filling ! Edited by - Mark W on 29 May 2006 10:32:50 Link to comment Share on other sites More sharing options...
Myles Posted May 29, 2006 Share Posted May 29, 2006 What oil pressure when hot does your R500 run at idle. I haven't got one... I use the R500-spec (i.e. 74 deg C) stat and matching radiator fan-switch in a 180+ bhp 1.8k. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
noddy Posted May 29, 2006 Share Posted May 29, 2006 Dave, Your oil pressure was running a lot lower than mine the other week when it should have been about the same. As for the ECU fan control, the bods a Caterham confirmed that it should cut in very early (about 65 deg C). R400 .......... I love it Link to comment Share on other sites More sharing options...
Myles Posted May 29, 2006 Share Posted May 29, 2006 Why? That means that the fan will be running continuously once the engine is up to temp. That's crackers. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
mav Posted May 29, 2006 Share Posted May 29, 2006 http://www.minister-power.com/support/engine_data_pages/cat_r400_data_page.htm here 75 degrees +/- 5 degrees... Link to comment Share on other sites More sharing options...
DSL Posted May 29, 2006 Share Posted May 29, 2006 My fan (R400) comes on around the 80c mark. I have recently had a problem with a stack oil pressure sensor on a Hayabusa engine which showed falling oil pressure under load & the occasional low pressure warning when over 6000rpm 😳 😳. Found out after a precautionary engine strip that it must have been vibration induced, as the motor was perfect. I have now mounted the stack sensor remotely on a braided hose, so far so good Link to comment Share on other sites More sharing options...
F355GTS Posted May 29, 2006 Share Posted May 29, 2006 but Minister run them without a thermostat Mark Link to comment Share on other sites More sharing options...
mav Posted May 29, 2006 Share Posted May 29, 2006 Mark (f355) Exactly! and they run at 75 +/- 5 degrees, so why would Caterham reccomend a 65 degree setting for the rad fan? Link to comment Share on other sites More sharing options...
Dunsfold Dave Posted May 29, 2006 Author Share Posted May 29, 2006 I have always run with the stack giving me a fairly low oil pressure reading and last year I did have the main oil pump replaced. Could the overheating be just a result of overfilling with oil. Once you over heat presumably the viscosity of the oil reduces and the pressure drops i,e 105deg water temp 5psi oil pressure?? The race engines running at 75+/- 5deg seems quite cool to me, but I suppose they dont sit in traffic for the temp to rise. DD DD Link to comment Share on other sites More sharing options...
Myles Posted May 29, 2006 Share Posted May 29, 2006 You certainly get noticeably-higher oil temps in a wet-sump if you overfill - but if the scavenge-pump(s) in a DS system are doing their job, there should be sod-all oil floating around in the sump to get whipped-up by the crank... The OP does drop as you heat the oil - but I don't think I've ever seen my OP drop below something like 20-25ish psi at idle after a hot track session - that's probably leaving the oil at around 90ish deg C from recollection with my engine. I doubt that an extra 15 degC would drop it further to 5psi, but I'm sure there are some engineers out there that could confirm it. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
susser Posted May 29, 2006 Share Posted May 29, 2006 One thing that helps cooling, whilst sitting in traffic etc is to rev the engine. Oh yes ❗ ❗ The water pump is a centrifugal type and at idle speeds does not spin fast enough to give a high pressure/ volume output. As the cooling is done by the rad, you need to deliver the hot water to it; Revving up to only about 2000 or so will allow the pump to shift more water. The heat produced by the engine will not be significantly more than that at idle, but the water pump will be operating further up it's pressure/volume curve. Just try it and watch the guage drop. If that doesn't happen, you have a problem elsewhere;, Stuck stat, shagged pump, radiator full of air, etc. IMHO susser (1/2 🙆🏻d thermodynamicist ) Link to comment Share on other sites More sharing options...
Peter Carmichael Posted May 30, 2006 Share Posted May 30, 2006 Have you checked which direction the air is blowing from the fan. It might be rigged to incorrectly blow forwards. This would work Ok at standstill on the drive but not when driving slowly. Link to comment Share on other sites More sharing options...
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