F355GTS Posted March 26, 2005 Share Posted March 26, 2005 Engine is new to me, all Steel, recently rebuilt. I had it mapped at Steve Greenald's last Tuesday and all went well except the fan didn't seem to be cutting in soon enough so it was rigged for manual operation, unfortunately it appeared to overheat (only 104 degrees) but coolant came out of the pressure cap. It wasn't bled although seemed to behave quite well untill sometime later Steve was mapping the higher rev areas (6.5k+) and then it spewed coolant from the cap althoug the ECU and Stack were reading mid 90's temps, We assuned an airlock from the earlier boil over but tested for hydrocarbons, there was a faint trace but the coolant had come from my old engine so theres no certainty that there is anything wrong with this one Today I took the car out, it seemd to behave impeccably, fantastic power etc etc, pushed it up into the 8k plus realm and when I got home there was a trail of coolant into the garage and then a huge puddle appeared all from the cap, temps were good all the time in the 80s/90's, Removing the cap and bleeding the rad shows a load of air in the rad. I've tried a different (known good) cap, bleeding the system and am sititng hoping somebody''s going ot tell me it's not the Head Gasket ☹️ Mark Edited by - F355GTS on 27 Mar 2005 16:41:19 Link to comment Share on other sites More sharing options...
pete g Posted March 26, 2005 Share Posted March 26, 2005 sounds like pressure cap problem to me, or air lock Link to comment Share on other sites More sharing options...
Paul McKenzie Posted March 26, 2005 Share Posted March 26, 2005 Sorry, Mate, but HG's gone What does 'recently' rebuilt mean? These engines do not like to sit around unused....I've seen three very low mileage ones with the HG gone....and did you really re-use coolant from your old engine Paul Edited by - Paul McKenzie on 26 Mar 2005 19:18:24 Link to comment Share on other sites More sharing options...
StewartG Posted March 26, 2005 Share Posted March 26, 2005 Have you fitted the restrictor in the pipe to the expansion tank? Link to comment Share on other sites More sharing options...
F355GTS Posted March 26, 2005 Author Share Posted March 26, 2005 Pete I have replacced the Cap Paul Sadly I think i know that you are right ☹️ Engine was rebuilt last Summer and then run in (in a Westfield ) since then it's been sitting doing nothing. It was rebuilt due to a bottom end failure of some kind, HG was replaced. I did reuse the coolant, yes, why would that be an issue? Stewart Unless it's already there then no but then that would mean it wasn't there for the last engine and that didn't suffer the same problems, which pipe does it go in, the one to the head or the one to the submarine hose Mark Link to comment Share on other sites More sharing options...
EFA Posted March 26, 2005 Share Posted March 26, 2005 Mark, Have you ensured there is no air in the system? Is the stat in the correct way up? Are you using the 82deg Turbo stat (this is the best one....) Airlocaks can the hard to eleiminate from the VX install in a Caterham. Jack up the front about 12" and let the temp get to 90 before you screw on the exp cap! Leave the rad bleed screw loose as well and ensure the top of the rad is full. WIth the ally rad, the fact the rad is hot does not necc mean its full. HG failures are very rare on a VX unless there is something else wrong. Link to comment Share on other sites More sharing options...
F355GTS Posted March 26, 2005 Author Share Posted March 26, 2005 Thanks Arnie Thermostat does open around mid 80's so I guess it's OK I'm going back out to the Garage now to have another go Mark Link to comment Share on other sites More sharing options...
Paul McKenzie Posted March 26, 2005 Share Posted March 26, 2005 Arnie, HG failures are very common on a VX which is not used. PaUL Edited by - Paul McKenzie on 26 Mar 2005 20:26:57 Link to comment Share on other sites More sharing options...
Paul Gibb Posted March 26, 2005 Share Posted March 26, 2005 Mark, I am afraid that I think Paul is probably right about this, my HG had lost its seal & behaved the same way (this was also diagnosed by Paul - see previous threads). Before changing the head gasket try Nick D's cooling mod for high revving vauxhalls - a self bleeding swirl pot/exp tank in the top rad hose. Unfortunately I am not sure whether the modified exp tank or the new HG cured my problem as they were both done at the same time! Paul L7 FUN Link to comment Share on other sites More sharing options...
F355GTS Posted March 26, 2005 Author Share Posted March 26, 2005 Paul thanks for that, I'l look for NickD's fix but not sure i can get it in as I have a Laminova in the top hose. Was it just an HG change on yours or do you have to skim the Head etc, IIRC the HG fitted is a Steel one supplied by SBD I've bled it eactly in line with Arnie's advice and fwiw the stat opens at exactly 82 degrees, too late to take it out now so will give it a run tomorrow and report back Mark Edited by - F355GTS on 26 Mar 2005 21:04:55 Link to comment Share on other sites More sharing options...
Paul Gibb Posted March 26, 2005 Share Posted March 26, 2005 Mark, The head was skimmed when the HG was changed. If you ever bump into my wife this is all that was done when the engine went back to Swindon 18 months ago (I think at the time I told her HG change + a few little bits & pieces ) Paul L7 FUN Link to comment Share on other sites More sharing options...
Swiss_Tony Posted March 26, 2005 Share Posted March 26, 2005 HG failures are very common on a VX which is not used. Can you explain why? Mark try another cap first as they are a common thing to fail. They are off a Rover after all James Su77on Se7ens Link to comment Share on other sites More sharing options...
Paul McKenzie Posted March 27, 2005 Share Posted March 27, 2005 James, I really don't know why , but it's an undisputable fact, as I said I've seen at least three in the last couple of years; one was Paul Gibbs' and the other two were friends of mine who had just bought very low mileage cars which had sat around for fairly long periods without use. These are just ones I've known first hand so I'm sure there are very many more If I had to guess on the cause I'd say localised corrosion between the gasket and the ally head probably accelerated by dissolved oxygen in the coolant (since the engine's not being run the coolant doesn't get hot and purged of air) Paul Link to comment Share on other sites More sharing options...
F355GTS Posted March 27, 2005 Author Share Posted March 27, 2005 Same problem after bleeding it as Arnie's suggested, changed cap again still a problem. I then removed the Thermostat and the problem seems to have gone away any clues as to why? Although I am convinced hte Thermostat was opeing in the car, a test in a Saucepan failed Mark Link to comment Share on other sites More sharing options...
EFA Posted March 27, 2005 Share Posted March 27, 2005 Mark, Be sure its in the correct way up, (not that that would affect the saucepan test)..... Otherwise replace it! I have had a dodgy stat in the past.......not as severe as your's though, just higher running temps when it was sticking. Link to comment Share on other sites More sharing options...
F355GTS Posted March 27, 2005 Author Share Posted March 27, 2005 Arnie thanks for the info, I can't see how it could be fitted upside down Mark Link to comment Share on other sites More sharing options...
EFA Posted March 27, 2005 Share Posted March 27, 2005 I think it may depend on the manufacturer of the stat, but I have found them like this before! Link to comment Share on other sites More sharing options...
oi oi Posted March 27, 2005 Share Posted March 27, 2005 cooling water plumbing is an issue with the Vx. have a read of sbd's website. if your not running a heater the easiest thing to do is plug the back of the head where the water would normally feed to a heater. if its not running a heater the water pump pumps throught the head and can pressurise the header tank, expecially at high revs. i spent a couple of years with lovely (wet) warm feet until i plugged the back of the head. Link to comment Share on other sites More sharing options...
ECR Posted March 27, 2005 Share Posted March 27, 2005 Mark Whilst it could possibly be a number of things, this looks suspiciously like the problem that I suffered (for months !) It eventualy lost me 2 days of Track time at Monza of all places so I was pretty fed up with it. The engine would run fine at lower revs but hit the loud pedal and thar she blew... I eventualy took the head off and there was only the slightest trace of a blown gasket (hardly visible and it could easily be missed) A skim and a new gasket and problem instantly solved. FWIW if you have to have the head off re fit it with ARP head studs (so much better than the standard GM bolts) BTW I run a feed to the rear of the head (with no heater fitted and suffer no problems ..... ?? Link to comment Share on other sites More sharing options...
F355GTS Posted March 27, 2005 Author Share Posted March 27, 2005 OI. OI/ ECR Rear Heater feed is blocked off I've not discounted the Head Gasket yet but seems odd that it appears ot be OK without the thermostat, I wonder hte the Laminova is causing a restriction I believe it has ARP head bolts Mark Link to comment Share on other sites More sharing options...
Paul McKenzie Posted March 27, 2005 Share Posted March 27, 2005 ECR has it precisely - my mates' engine builders reported exactly that . Don't expect to see Etna's crater when you examine the gasket Paul Edited by - Paul McKenzie on 27 Mar 2005 20:20:34 Link to comment Share on other sites More sharing options...
EFA Posted March 27, 2005 Share Posted March 27, 2005 I see no problem with the GM head bolts- I use them 6 times AND I am probably running the highest compression ratio of all of us! Any issues with high revs and discharge of coolant I would also dismiss - I drive my car hard and it regularly hits its 9300rpm soft limiter! I have no mods to the top hose! Reading your post again, the reason it blows the coolant when you get home is the lack of cooling. If the fan is not working 104deg will be enough to blow any cap! These engiens should not be running at over 90 deg if set up properly, unless in traffic, and the kenlowe will take care of things under these conditions if working properly. Have you thought about an ECU derived signal for the fan? The rad switches are notorious for failing! I really do not subscribe to the HG theory- expecially if the engine has been out of the car - i'e no coolant. Link to comment Share on other sites More sharing options...
captain chaos Posted March 27, 2005 Share Posted March 27, 2005 I was at Spa last year with Paul Gibb and Nick D. I was losing coolant (blowing out the cap when driven hard)...we all diagnosed HG....then I discovered the hose between the heater and the back of the head was not done up tight enough and was drawing in air which pressurised the system. Tightened the clip and heypresto all OK. The 2 days at Spa were brill. The hose would not leak at tickover or light revs so it was tough to spot. Just check everything is done up correctly before you go looking for more difficult issues to solve. Good luck. Link to comment Share on other sites More sharing options...
Bob Simon Posted March 27, 2005 Share Posted March 27, 2005 I had similar experiences as well. turns out the theromstat was somewhat selective in it's functioning. sometimes it worked and sometimes not. Sauce pan test confirmed this. Replaced it with 82° turbo bit and have had no trouble since. [thread hijack] I binned my heater when the car went on a diet. The heater hoses where then spliced together. Can I remove the heater hose and plug the back of the head and submarine pipe alltogether? Do any other hoses need to be eliminated to get proper flow through the head? What about the 16mm hose from the submarine pipe to the Caterham intake manifold? (45DCOE CC manifold) [/thread hijack] -Bob 94 HPC VX Link to comment Share on other sites More sharing options...
pete g Posted March 27, 2005 Share Posted March 27, 2005 [8then I discovered the hose between the heater and the back of the head was not done up tight enough and was drawing in air which pressurised the system. Tightened the clip and heypresto all OK o] not specifically true,if pipe was loosethe pressure in system would drop ,allowing the coolent to boil at a lower temperature ,therefore causing water to turn to steam which will expand very quicky and pressurise the system and blow the pressure cap, Link to comment Share on other sites More sharing options...
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