Paul Gibb Posted July 1, 2003 Share Posted July 1, 2003 Your help & advice required please guys. Are the following symptoms of head gasket failure? Since acquired L7FUN has tended to run hot on trackdays, but the tendency has been more noticeable this year following winter rebuild. Water temps can reach 100-105, and oil temps peak at 115. Radiator is thick Vx race aluminium c1995. First time out at Cadwell in early May the water pump seal blew spraying coolant over block. Pump & seal were replaced in time for Brands mid May apparently solving the problem but now some coolant appeared to be fizzing from the expansion tank cap when hot. The problem reappeared on the second of two days at Spa in late May with temps as above and the engine apparently performing normally. After d/w Swindon an 82 degree thermostat was fitted (the old 94 degree thermostat appeared to be broken) and I began considering new rad/oil coolers, mods to the exp tank etc. Today at a wet Oulton a misfire detectable at around 7000rpm and more coolant fizzing from expansion tank cap onto cambelt cover & offside engine bay led to an early bath. Performance seemed to be normal in the only dry session of the day. How can I establish the diagnosis? Will the treatment involve major surgery? How can I pursuade my wife that participating in Arnie's piston bulk buy may be unavoidable? Thanks in advance, Paul L7 FUN Link to comment Share on other sites More sharing options...
allen Posted July 1, 2003 Share Posted July 1, 2003 Paul, I'm not a VX owner/expert but the temps you quoted do not seem too bad for hard track day use. Pressurised cooling systems are designed to run at over 100C and a good synthetic oil can cope this the temp you quote. Could it be getting worse because you are gradually driving faster? A decent garage will be able to take a sampe of coolant and check it for combustion gasses - if it fails it is head gasket, if it passes you have eliminated the expensive option - if you are concerned - don't guess, have the test done. When the water pump went it may have caused overheated, causing the head gasket to go, however - If you have the K type header tank, the plastic cap needs replacing if it has 'blown off' 🙆🏻 😬 Link to comment Share on other sites More sharing options...
ECR Posted July 2, 2003 Share Posted July 2, 2003 Could very well be a gasket failure but as Allen says get the coolant checked for combustion gasses (they replace the header tank cap with a cap that has a pipe running from it to a tube containing a liquid. If this changes colour you have a gasket problem) I would replace the header tank cap as a matter of course Halfords HRC606 0.8 to 1.2bar opening pressure They are very cheap. I had a continual problem with coolant coating the engine untill I replaced the cap. If the gasket has gone you will(unfortunately) probably find that the face of the head has eroded and it needs stripping down, weld repairing and re skimming. This is very successful so dont worry Link to comment Share on other sites More sharing options...
ECR Posted July 2, 2003 Share Posted July 2, 2003 Could very well be a gasket failure but as Allen says get the coolant checked for combustion gasses (they replace the header tank cap with a cap that has a pipe running from it to a tube containing a liquid. If this changes colour you have a gasket problem) I would replace the header tank cap as a matter of course Halfords HRC606 0.8 to 1.2bar opening pressure They are very cheap. I had a continual problem with coolant coating the engine untill I replaced the cap. If the gasket has gone you will(unfortunately) probably find that the face of the head has eroded and it needs stripping down, weld repairing and re skimming. This is very successful so dont worry Link to comment Share on other sites More sharing options...
captain chaos Posted July 2, 2003 Share Posted July 2, 2003 Hi Paul, I never thought of the cap being a problem yesterday so that could be a real cheap fix Get the coolant checked...whatever the results...tell the wife it's terminal and you need a new set of Pistons 😬 Let me know how you get on Link to comment Share on other sites More sharing options...
Paul McKenzie Posted July 2, 2003 Share Posted July 2, 2003 Hi Paul, I was the bearer of bad tidings to you yesterday whan I told you it was the head gasket. Excuse me for reiterating it here, but it could be useful for other XE owners. As I told you I've seen this problem firsthand twice in the last couple of months with XE's. The symtoms you described were exactly the same and in both cases the engines had stood idle for a good period of time, like yours had I believe. The head gasket had gone in both cases and both required the head reskimming. In both cases we fist tried new header tanks, caps but to no avail. Like yours the performance of the engine seemed unnafected. Whip the head off, and I think you'll find we were correct. Paul Link to comment Share on other sites More sharing options...
captain chaos Posted July 2, 2003 Share Posted July 2, 2003 Just hijacking this thread briefly..(sorry Paul) Roger and Paul, If you are using your car for a track day, do you know roughly how many hard miles you get to a full tank of fuel ( I take it you are both on TB's) and what do you get if you are generally blatting? thanks Gary PS Roger, Got a lovely note from your wife today I'm in for my first club sprint! Link to comment Share on other sites More sharing options...
I reply to every thread Posted July 2, 2003 Share Posted July 2, 2003 Paul ,as I remember, is on those very sexy Swindon Roller-barrels. Link to comment Share on other sites More sharing options...
captain chaos Posted July 2, 2003 Share Posted July 2, 2003 Sorry I mean't Paul Mackenzie as I've seen Mr Gibbs lovely rollers! Link to comment Share on other sites More sharing options...
Paul McKenzie Posted July 2, 2003 Share Posted July 2, 2003 Captain, I'm on Weber 45's, properly jetted and with 3D ignition I get 16-17mpg 'normal' driving, and half that on track. Paul Link to comment Share on other sites More sharing options...
Paul Gibb Posted July 2, 2003 Author Share Posted July 2, 2003 OK guys, many thanks to Allen, Roger, Paul, Gary (and hi to Matthew) for the very helpful comments. Coolant has just tested negative for combustion products which made me feel a little better. With engine run up to temp thermostat opened at 82 and fan came on at 90. Coolant rapidly filled expansion tank & began running briskly through the vent at the top of the testing syringe producing a mini fountain to a height of around 5cm - is this normal? I now need a little time to think before deciding how bestr to proceed. Dave,Gary, Mav, Fred et al great to meet up with you all yesterday. Paul L7 FUN Edited by - paul gibb on 2 Jul 2003 14:19:34 Link to comment Share on other sites More sharing options...
Paul Gibb Posted July 2, 2003 Author Share Posted July 2, 2003 Roger, Just found your attached file - thankyou. Paul, Did your 2 XE engines pass or fail the coolant test prior to head removal? L7 FUN Link to comment Share on other sites More sharing options...
Paul McKenzie Posted July 2, 2003 Share Posted July 2, 2003 Paul, It wasn't checked in either case as, unfortunately, the symptoms are unmistakeable. Paul Link to comment Share on other sites More sharing options...
I reply to every thread Posted July 2, 2003 Share Posted July 2, 2003 Paul - Completely O/T - but thanks for what you did for me last September. I walked 14 miles on Saturday up hill & down dale (Teesdale actually) That would have been an impossibility a year ago Link to comment Share on other sites More sharing options...
rjc Posted July 2, 2003 Share Posted July 2, 2003 If the engine is run up to temp without the pressure cap, water can come spouting out driven by boiling in the block which can produce a powerful fountain of scalding hot water. If you suspect a popped cylinder head gasket then surely you should do a compression check as the next step. You can source a Gunsens's Hi Gauge at any branch of Halfords it's by no means the best compression gauge but it is adequate to spot a blown gasket. Get the engine warm, whip out the plugs and get someone to sit in the car and crank the engine a few times with the throttles wide open. Do each cylinder in turn (watch out for flattening the battery). If the cylinder head gasket has blown one piston will record a much lower compression than the others. If they are all even it's summat else. As suggested previously put a new pressure cap on. Check the coolant hoses, sometimes they leak and produce an effect similar to a head gasket failure. Check for cracks, especially around where they are secured with the jubilee clip. I had a nasty case of boilup once where a jubilee clip to the rad actually fractured and fell off. Take out the thermostat and drop it into a pan of boiling water - does it open fully ? Has the drain plug in the radiator worked loose, is the radiator leaking ? Whipping the head off is a major step and should be saved until you've elimated any potential faults with the cap, thermostat, hoses, jubilee clips and the radiator. Usually (but not always) water comes dribbling out of the side of the gasket at the site of the fault so check for dried leak marks down the sides of the engine. Following any boil up, be carefull to bleed the coolant system well and properly. Lots of follow on damage can result from not clearing all the airlocks when refilling the system, and having another boilup on a partially full system. Link to comment Share on other sites More sharing options...
StewartG Posted July 2, 2003 Share Posted July 2, 2003 Do you have the restrictor in the pipe going to the header tank? Link to comment Share on other sites More sharing options...
Paul Deslandes Posted July 2, 2003 Share Posted July 2, 2003 The VX engine cooling system can be a b***** to bleed. Jack the front of the car up as high as you can (running it up the ramp of a trailer is effective) and run the engine from COOL with the header tank cap off and the top bleed plug of the radiator loose or removed. All this taking the usual precautions re scalding water. Keep topping up until all the air is out. This will ensure that the engine is bled out properly. If it still overheats look elsewhere. Link to comment Share on other sites More sharing options...
EFA Posted July 2, 2003 Share Posted July 2, 2003 Paul, Good to see you on the M25 last night...... I've been trying to get in touch as I have some questions regarding the Swindon TB's on your car. Perhaps you could call me at a convenient moment 07710 526739. 5cm of water out of the header tank is also normal when the stat opens. When the cap blows, what water temp do you have on the gauge? Are you sure there are no airlocks in the system - the XE can be a pig at times to remove them. If there are no combustion gasses in the coolant, and no white sludge in the oil, (take the top cover off the engien) then HG seems unlikley. Seeing what you car has been through, I think its quite likely it could be air in the system. Bleed it at the top of the rad. Call me and I'll describe the best proceedure. Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Link to comment Share on other sites More sharing options...
EFA Posted July 2, 2003 Share Posted July 2, 2003 Seems Paul posted at the same time as me! Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Link to comment Share on other sites More sharing options...
Paul Gibb Posted July 2, 2003 Author Share Posted July 2, 2003 Thank you all for the advice. Rowland, Compression check & new exp tank cap tomorrow or Friday & I will post results. Thermostat is new 82degree supplied by Swindon & appears to be working OK. Stewart, There is no restrictor in the pipe from manifold to exp tank. I bought one from Caterham but it does not appear to fit. Could this be important? Paul & Arnie, I will rebleed v carefully after compression check as you describe. Arnie, Cap only noted to have blown after track day sessions not rare 'normal' drives. Water temps max at around 105 indicated on track - v rarely exceed 100 at any other time. Driving home yesterday feeling miserable I was cheered up considerably by the sight of R500SUX and your friendly wave - about 2hrs earlier I had been buzzed by Jerry Pike returning from a bike day at Donington.Too late to ring you now but I will phone tomorrow. Paul L7 FUN Link to comment Share on other sites More sharing options...
NickD Posted July 3, 2003 Share Posted July 3, 2003 Paul, As discussed before, I had exactly the same problems with the expansion tank on my car. The Caterham-supplied tank has two faults - 1: It is mounted too low - ie below the water level at the top of the cylinder head and 2:It feeds into the (low pressure) inlet hose to the water pump, with a (high pressure) return pipe from the top of the head by the inlet manifold. While the system is almost OK on standard engines, it just doesn't work once the revs get above about 7500. The air in the expansion tank tries (and always succeeds, in my experience) to reach the highest point in the system, the cylinder head. The engine then starts to overheat (which often goes unnoticed as the water temperature sensor in the thermostat housing may read low as it is now surrounded by air rather than water). The thermostat is also in air for much of the time and so may be fooled into not opening properly. The expansion tank is now 100% full of water which gets blown out via the cap as the system overheats and the pressure rises. The low pressure feed/high pressure return to the expansion tank only aggravates this problem. Caterham started to fit a non-return valve in the return pipe to the tank in an attempt to control this cycle but, while this helped, it didn’t solve the problem as the fundamental cause is point 1 above. Fitting a lower temperature thermostat is a good idea as this can help prevent everything overheating to the point where water is blown out. This may be OK for the road but go to a fast circuit (eg Spa or Goodwood) where 8000+ rpm are used for long periods and the problem reappears. Bleeding the system restores the air and water to their correct positions, but not for long! Anyway, enough of the problems, and on to what can be done to correct this. On my car I removed the plastic expansion tank and blanked off the inlet into the bottom hose. I then had an aluminium swirl pot made which is inserted in the top radiator hose. The return pipe from the head by the inlet manifold is also fed into the swirl pot. The swirl pot is now at the highest point in the system, which therefore becomes self-bleeding. I have used this system for four years and it never blows out any water at all and the water temp stays in the 80s even with 8500rpm circuit use on hot days. Link to comment Share on other sites More sharing options...
jerrypike Posted July 4, 2003 Share Posted July 4, 2003 paul good to see you too, long wet day would agrre with the pre head gasket checks, friendly mechanic can do these very quickly hope all sorted easily jerry Link to comment Share on other sites More sharing options...
Paul Gibb Posted July 4, 2003 Author Share Posted July 4, 2003 Nick, Very many thanks once again - I will attempt to replicate your set up on my car. After studying the pics I have a couple of quick questions which I have emailed to you off line. Jerry, I am amazed that you can whistle that loud! Paul L7 FUN Link to comment Share on other sites More sharing options...
jerrypike Posted July 4, 2003 Share Posted July 4, 2003 such a useful social skill sorry to disturb your reverie jerry Link to comment Share on other sites More sharing options...
Paul Gibb Posted July 6, 2003 Author Share Posted July 6, 2003 My overheating & coolant spraying problems have been cured (temporarily at least) by a careful bleed (as described above), the insertion of a restrictor into the pipe connecting manifold to exp tank, and a new exp tank cap. Total cost £5.50!! Nick D's cooling mod in progress. Fingers toes etc remain crossed. Thanks all once again, over & out Paul L7 FUN Link to comment Share on other sites More sharing options...
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