opplock Posted August 22, 2002 Share Posted August 22, 2002 My x/flow (1700, 254 cam)has suffered overheating problems for more than 2 years. Until a few months ago water temp stayed below 100 unless in heavy traffic or below about 45mph. Now temp drifts up to about 110 within 10 miles & stays there. Last time out (Saturday evening) temp off end of scale, oil pressure dropped to approx 0. Cooling system has been tested numerous times & works perfectly in workshop. Most cooling system components have been replaced in last 2 years, override switch fitted .... Only cooling system mod not yet tried is ali rad. Head gasket was replaced in June. Any ideas? Link to comment Share on other sites More sharing options...
allen Posted August 22, 2002 Share Posted August 22, 2002 How old is the car - if it is of a certain age (more than juat a few years) it may have a partially blocked up radiator - you could use rad flush, you could take it off and use a hose to back flush it - or have it re-cored or buy a new one - sounds like an engine re-build might be in order too if you ran for long with no oil pressure. ☹️ good luck (I am assuming you have checked the coolant for combuastion products, that you are sure the thermostat is OK likewise the water pump (just cos it's new doesn't mean it has to work!) Link to comment Share on other sites More sharing options...
opplock Posted August 22, 2002 Author Share Posted August 22, 2002 Radiator is 4 years old. Drained system (the remaining 1 litre) & flushed rad last night, no blockage. I'm reluctant to pay for rebuild at present - throwing good money after bad? Beginning to think that replacement with Zetec might be more sensible. Link to comment Share on other sites More sharing options...
allen Posted August 22, 2002 Share Posted August 22, 2002 Don't sound like it's the rad then (wouldn't really expect it on a 4 year old rad) Have you had the coolant checked for combustion gasses? Is the waterpump working properly? (if you run it up from cold with the rad cap off can you see it thrashing the water round, especially when reved?) Have you tried running it with the thermostat removed? Link to comment Share on other sites More sharing options...
opplock Posted August 23, 2002 Author Share Posted August 23, 2002 Thanks for the advice. Water pump working fine, at least while car is stationary. Ran the car without thermostat for a few months when problems started. Took hours to reach 80 degrees, didn't stop overheating. Redline have checked the cooling system a few times & can't find anything wrong. Excuse my ignorance, by combustion gasses are you suggesting petrol & coolant are mixing? What would this mean? A friend swears the problem is a cracked block. Mind you he knows nothing about x/flows. Link to comment Share on other sites More sharing options...
Harvey Posted August 23, 2002 Share Posted August 23, 2002 Apologies for stating the obvious, however I have encountered many people who have fallen foul of the same error. Is the fan operating in the correct direction? I had similar problems with my x flow, which was resolved by putting a larger expansion tank in, allowing more water/coolant in the system. Do you have one fitted? Link to comment Share on other sites More sharing options...
Joe 90 Posted August 23, 2002 Share Posted August 23, 2002 Combustion gases in the coolant are a sign that the problem is with the engine and not with the cooling system. A pretty good way of testing this is to put a CO meter into the expansion tank (not in the water, into the air). If you can measure any CO, then it might well be a cracked block, a cracked head (v. common of tuned x/flows), warped head, head gasket etc. A poorly tuned engine generates more waste heat, so other things to check are mixture and timing. An engine will run hotter if the timing is too advanced or too retarded. Does it overheat in traffic/idling or at high speed/high rpm? 98,000 miles so far Link to comment Share on other sites More sharing options...
opplock Posted August 23, 2002 Author Share Posted August 23, 2002 Fan operating in wrong direction - hadn't thought of that. It might explain the recent experiences. Will check this weekend, I assume it should rotate in clockwise direction? Head gasket was replaced & head skimmed in June.Timing etc put right in July. Car has done approx 60 miles since. My gut feeling is that it is an engine rather than cooling system problem. With previous x/flow (admittedly lower spec) I could do 500 miles in a day, including a 100 mile race, without ever exceeding 90 degrees. Link to comment Share on other sites More sharing options...
Harvey Posted August 24, 2002 Share Posted August 24, 2002 Clockwise/anti clockwise- depends on whether your fan is in front, or behind the radiator. Operate the fan and you should be able to see as it starts/stops. Most will change direction by simply changing over the terminals. Good luck. Link to comment Share on other sites More sharing options...
greg Posted August 24, 2002 Share Posted August 24, 2002 Very stupid question, but is the sender ok? And are you postive there is no airlock/sufficient water etc ... Greg, Q 86 NTM (Green 185BHP XF) Link to comment Share on other sites More sharing options...
opplock Posted August 24, 2002 Author Share Posted August 24, 2002 Fan is in traditional position behind radiator & is operating correctly. Sender was OK until last weekend but now reads max as soon as I switch on electrics. Since problems started I've been in the habit of topping up coolant before driving anywhere. System has been drained & tested so many times I can't believe the problem is an airlock. Link to comment Share on other sites More sharing options...
ashaughnessy Posted August 25, 2002 Share Posted August 25, 2002 I''m a bit surprised at the temperatures you quote as being the "normal" temperatures. You''ve said the temperature always stayed below 100, you''ve also said that your previous engine never exceeded 90 degrees. I would say the "normal" temperature would be about 78 degrees when motoring along smoothly and it will go up to about 95 or so when stuck in traffic, at which point the fan will come on and bring it down to high 80s or 90. If your engine wasn''t doing this when it was working, then you may have had a problem earlier. The combustion gas thing can be checked very simply. A chemical test of your coolant will show this up. You just have to extract a sample of coolant and do the chemical test. You can buy these testing kits yourself or take it to a local garage who can do it. The test will show whether you have the combustion gases from the combustion chamber contaminating the coolant. If you do, it means either a crack in the block or a leaking head gasket. Another fix is to convert to a fully sealed cooling system. This replaces the filler neck at the thermostat housing with a different one that doesn''t have a filler cap. You then use a remote header tank to fill up. This should remove any possibility of losing any coolant. However, for normal road use you might say that this would just mask any problem rather than fixing it. Roger King can do a conversion kit for a reasonable price. Have you noticed whether you are losing coolant? With the normal non-sealed system it is difficult to tell because it will lose water as a matter of course. Other things to check might include the inlet manifold. There is a water inlet port to the head at that point and it is easy to get a water leak from there. This might be because the manifold/head joint isn''t good or because the central mounting stud for the manifold isn''t properly fitted. This has given me problems in the past and caused water loss. I would also be worried about the effects of the incident where the temperature went off the scale and you lost oil pressure. This episode might have done a lot of damage (warped head, damaged bearings, etc). Anthony Link to comment Share on other sites More sharing options...
Peter T Posted August 25, 2002 Share Posted August 25, 2002 Franckly i would suspect the gauge, if you say that it gets up to these temperatures and runs normally, then i would recomend that you subsitute the gauge and sender for another unit. Most x-flows will not tolerate usage in these upper zones that you are quoting without failure of the headgasket, unless you are using a steel gasket, and a very high compression ratio, or a very weak mixture and low quality fuel! C7 PWT X-Flow all Steel Life begins at 40(00rpm) Link to comment Share on other sites More sharing options...
opplock Posted August 28, 2002 Author Share Posted August 28, 2002 I have decided on engine rebuild & will investigate using sealed system. Thanks to all for your advice. Link to comment Share on other sites More sharing options...
puremalt Posted September 1, 2002 Share Posted September 1, 2002 Thanks for the advice too chaps. My 13 year old x flow runs at 90-95 degrees all the time. Replaced sender with a new one and it didn,t get over 40! Got the old one cvleaned up and much better, although I am definitely losing coolant. There is some mayo on the base of the dipstck, I was told it was because the car was idle for 6 months before I bought it. I have a cork head gasket, any comments? Dave Robertson Link to comment Share on other sites More sharing options...
Big Brother Posted September 1, 2002 Share Posted September 1, 2002 "I have a cork head gasket" That could be the problem! Steve Se7en-Up! One day, all cars will be made this way! Link to comment Share on other sites More sharing options...
ashaughnessy Posted September 2, 2002 Share Posted September 2, 2002 Dave, I presume you mean a cork rocker cover gasket, not head gasket? I hope you do. Cork is the standard material for the rocker cover gasket. Mayonnaise oil is not right but if it's been idle for six months who knows what state its in. Change the oil and filter, flush through, and see what happens. Do you have a fully sealed cooling system or the normal one with the filler neck on the thermostat housing? If the latter it will always lose water, the real question is how much is normal - can't really answer. It should run above 40, if it doesn't get above 40 I'd keep checking things out. Perhaps your thermostat is stuck open? Even so, it should get above 40 degrees, especially in slow traffic in town. Anthony Link to comment Share on other sites More sharing options...
puremalt Posted September 3, 2002 Share Posted September 3, 2002 Two weeks on holiday and my brain is addled. Yes it is the rocker cover gasket that is cork. I am planning a service/oil change very soon. The new(old) temp sender shows typically 90C during normal running, the fan comes in at around 100C. BTW the seven started on the 8th turn of the key after 3 weeks idle. My brand new volvo broke down on holiday after 9 weeks of use. "If only everything in life was as reliable as a 7" Dave Robertson Link to comment Share on other sites More sharing options...
millsn Posted September 3, 2002 Share Posted September 3, 2002 My zetec has its temp sensor immediately after the point where the water leaves the head. therefore you see the actual exit temp of the water, not the temp that the engine actually sees. Where in the water circuit is your temp gauge sender and is it the correct one for the gauge? Also - I see a higher temp reading from my gauge when the earth to it is dodgy. I.e. if I switch on the lights my temps appear to go up. Is your earth doing a good job? Your gauge will over-read if it isn't. Nigel Mills - 2.0 Zetec carbs Edited by - millsn on 3 Sep 2002 19:32:59 Link to comment Share on other sites More sharing options...
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