steve@cornwall 100 Posted August 6, 2006 Quick question- There's a small bore pipe from the expansion tank to the top of the radiator. on my spare rad. the plastic tube is broken- can I just blank the hose and small hole in the rad? It would seem that I'll still have flow through the rad and the expansion tank has an overflow anyway. Any thoughts/experiences? Cti doesn't like this weather and overheats at a "good" speed. Have re-set timing, bled system, removed stat and replaced expansion cap, so next logical step would seem to be replace rad?- plenty of pressure through bleed point when running from cold- all pipes pressurise-heater works fine so I reckon water pump is o.k. Share this post Link to post Share on other sites
Jonmurgie 2 Posted August 6, 2006 I believe you may need that overflow pipe but I'll see what others say As for the over heating, have you done a compression test? Share this post Link to post Share on other sites
steve@cornwall 100 Posted August 6, 2006 I believe you may need that overflow pipe but I'll see what others say As for the over heating, have you done a compression test? I was trying not to think about that! Thing is, when left idling,the fan cuts in and the "stop"light doesn't come on. lt only gets that hot when driving over "60" mph. (obviously I never go above70!). Backing off to 45-50 and the temp lessens. Also the car starts so well, turn the key and fires on just about the first cycle-just doesn't seem that water could be entering the bore (please,please, please), drove it carefully for 60+ miles today without losing any water too. Am I just in denial as I fitted my spare engine to another car last Monday? Very possibly. Share this post Link to post Share on other sites
jackherer 543 Posted August 6, 2006 I believe that pipe is there to allow air out of the top of the rad back to the expansion tank, you shouldn't run without it. Have you reverse flushed the coolant system to get all the gunk out? It sounds like your rad may be blocked to me. Share this post Link to post Share on other sites
steve@cornwall 100 Posted August 6, 2006 I believe that pipe is there to allow air out of the top of the rad back to the expansion tank, you shouldn't run without it. Have you reverse flushed the coolant system to get all the gunk out? It sounds like your rad may be blocked to me. O.k, Thanks,guys- Won't try to run without it then! Will backflush tomorrow (After the beach ) and let you know Share this post Link to post Share on other sites
Guest CB-Dave Posted August 6, 2006 certainly sounds like the rad, usually it wouldn't overheat if you're on the move cos the airflow through the rad keeps it cool... I've never ever had success at flushing a rad out when it's gunked up that much personally... I'd be more inclined to take it out of the car and blast some water through it under pressure, if that doesn't work then just buy a new rad - they're only buttons (under 30 quid iirc) Share this post Link to post Share on other sites
richard 0 Posted August 7, 2006 If your worried about the HG, then run it without the expansion tank cap off. You'll see lots of bubbles and smell exhaust fumes if the HG is leaking between the bore. If you're friendly with a garage, get them to put the emissions analyser into the expansion tank...that will tell you for definite. Share this post Link to post Share on other sites
Rob_the_Sparky 9 Posted August 7, 2006 yeah, block up rad or partly-opening thermostat would be my guesses. Share this post Link to post Share on other sites
steve@cornwall 100 Posted August 7, 2006 Just removed rad- about 70% of the cooling vanes have disintegrated!- no sign of sludging though! I've fitted a spare rad- this one was rather heavy and has 36 rows rather than the 26 row item removed- don't know what that's about, diesel maybe?. ran it up to temperature- took about 35 mins idling before the fan cut in and then went for a drive- the guage fell Will give it a good blast tonight and see for sure. Tightwad tip for today:- A broken overflow pipe on the rad can be replaced by drilling out the broken plastic to size and screwing in a fuel-reg takeoff pipe taken from an old inlet manifold. Share this post Link to post Share on other sites
steve@cornwall 100 Posted August 8, 2006 Been out for a couple of trips- still overheating It will do the 11 miles to our favourite beach though Latest bodge is to wire the slow speed fan to the ignition- let's see if that gets a bit further! Compression test looks likely to be needed though- if h/gasket is gone it will probably be the technical solution of crossing fingers that it stays driveable for the summer, until the mi goes in although I would prefer to get the engine right to put aside for a spare- finances won't allow it all. Share this post Link to post Share on other sites
Rob_the_Sparky 9 Posted August 9, 2006 Could still be a thermostat, if you haven't done this already... Share this post Link to post Share on other sites
steve@cornwall 100 Posted August 9, 2006 Could still be a thermostat, if you haven't done this already... good thought, currently running with NO stat, though- pretty definitive test! Spent a nice day on Scilly Isles today, and had to use the gti for the trip to Penzance, so no trial today! Cheers for the suggestion though, keep 'em coming (Have noticed the coolant level sensor is falling apart, so a slim chance that the system is not pressurising properly), and when the "stop" light comes on now there is no sign of boiling like before.Possibly the water temp sender is damaged now and telling fibs? I got a new one with a package of spares so will fit one and see! Doesn't smell overhot either. The new rad is also noticeably cooler after a run- leading to the fan sensor not coming on as readily (according to guage reading). Are there any checks for water pump efficiency? Rad cool/ engine hot- = circulation probs? (Or just overheating engine and rad trying Really hard---+ more denial?) Share this post Link to post Share on other sites
