mrfish Posted April 24, 2012 Share Posted April 24, 2012 I have been having over heating issues. So after replacing the rad, pump and stat I am now replacing the gauge and sender. I decided to plump for a VDO gauge and sender. They have now arrived but I am not sure how to connect the sender. It is a 1/8" npt thread, but i had been expecting a blade connector. Instead it has this and not a clue how to connect it: Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 24, 2012 Author Share Posted April 24, 2012 What an idiot! just figured it out Quote Link to comment Share on other sites More sharing options...
Frax Posted April 24, 2012 Share Posted April 24, 2012 Ye they look strange but that is how they work which is not a bad idea when you think about it, connector and wire can face any direction you require. Quote Link to comment Share on other sites More sharing options...
western Posted April 24, 2012 Share Posted April 24, 2012 As shown above if you use a fully insulated spade terminal, just cut part of the insulation away to let the terminal fit the button, worked for me. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted April 24, 2012 Share Posted April 24, 2012 Whats wrong with a normal stud and nut, although, having just returned a faulty sender for not being able to tighten the nut due to the guts spinning round..... Quote Link to comment Share on other sites More sharing options...
Marks 110 Posted April 25, 2012 Share Posted April 25, 2012 Will be interested to see the results as had similar problems and have also installed a vdo gauge Quote Link to comment Share on other sites More sharing options...
Michele Posted April 25, 2012 Share Posted April 25, 2012 What an idiot! just figured it out Been there, done that! And it took me a while Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 28, 2012 Author Share Posted April 28, 2012 Well i fitted the new VDO gauge and sender and the damn thing is still showing as overheating. It slowly rises to 90 then just carries on climbing to 120. No horrible smells or kettling from the engine. The history of the problem goes back to when i had to have the engine removed and re-sleeved. This was the first time the radiator system had been disturbed since I had it. Found that the stat was missing and the bypass pipe blocked. When refitting the engine I fitted a new stat and removed the block in the bypass. The engine was tested and sat at mid temp for over an hour. Since then it has shown overheating on a run. The top hose split so i replaced it. Then changed the stat for another new one. No change. Since then I have replaced the radiator, pump and fitted the new gauge and sender. I also tried fitting a new cable direct from the sender to the gauge as well as a new ground cable from gauge to bulkhead. There are no signs of contaimnation of either oil or water. Next job is to redo the earth at the battery (I have a dual battery setup from National Luna) and redo the battery to chassis and gearbox. At this point in time I am tempted to keep the new gauge and fit a new car to it! Quote Link to comment Share on other sites More sharing options...
western Posted April 28, 2012 Share Posted April 28, 2012 is the engine earthed to the chassis ? if no, fit a earth cable from the block/alternator/PAS pump bracket to the chassis part of engine mount. are the wires on the gauge on the correct terminals ? Quote Link to comment Share on other sites More sharing options...
Edlen Posted April 28, 2012 Share Posted April 28, 2012 I have a vdo temp gauge and sender and they work fine. I do not wish to insult you but are you sure there are no air locks in the system at all? Quote Link to comment Share on other sites More sharing options...
Marks 110 Posted April 29, 2012 Share Posted April 29, 2012 Surely if the temp was really 120 the coolant would be boiling? Sounds like a wiring issue to me. Can you see the point when the stat opens? On my 200tdi the gauge (vdo also) gradually rises to about 85 then suddenly drops back about 5 degrees as the stat opens and cool water is allowed to flow through the radiator. It will then gradually rise again and settle between 85-90 depending on how hard the engines working. Hope you sort it. Mark Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 29, 2012 Author Share Posted April 29, 2012 Redid the earthing point today with no effect. Checked the wiring and it seems ok. When i pull the connector off the sender and touch it to the engine block the guage goes full scale. Checked resistance between engine block and bulkhead and chassis which all seemed fine. Added a 16mm cable between the engine at the starter and the chassis. When the vehicle is just sitting there it will idle at about 85 all day, it is only out on a run that it starts to show a temp rise. The rise to 88 is slow and steady and the rise to 120 is pretty quick. it returns fast to 88 when i come to a stop. I have tried to make sure there are no airlocks, however my friendly local mechanic managed to snap off the plug on top of the thermostat housing and then araldited it back on! I have another housing on order but it will take about 10 days to get shipped to me. What i have done is take the plug out the top of the rad and confirmed it to be full. Then small hose on top of the stat housing that goes to the expansion tank and squeezed both top and bottom hoses and water comes out. What else can i do in the meantime to check for airlocks? What i am concerned about is the possibility of have a problem with the head gasket that causes gases to enter the cooling system. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted April 29, 2012 Share Posted April 29, 2012 Try the heater matrix pipes for air as well. Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 29, 2012 Author Share Posted April 29, 2012 Good thinking. I never use the heater normally it is too hot here (Zambia). As soo as the small group of elephants outside the fron of my house has decided to move elsewhere i will go and see. Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 29, 2012 Author Share Posted April 29, 2012 Disconnected the heater pipes and topped up as much as i could until it overflowed from the expansion tank then refitted. Used lots of rapid massaging of the top and bottom to get out any air and then closed the expansion tank. Ran her up to normal temp at idle. Water came out of the expansion tank in a few splurts (presumabley the overfilling). Took her on a drive and soon showed 120 again. So i put heater on to full but the air coming out did not feel very hot to me. I will redo the cables to the gauge once again incase the connector is no good. Does anyone know what resistance i should be reading on the VDO sender when running at 85c? I am reading 47ohms at the gauge end between the sender connector and the earth connector. Quote Link to comment Share on other sites More sharing options...
western Posted April 29, 2012 Share Posted April 29, 2012 the heater control only work the air flow flaps, the heater itself is a full flow type, there isn't a water flow on/off valve to worry about, might be worth having the cooling system pressure tested, any decent garage should be able to do that. Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 29, 2012 Author Share Posted April 29, 2012 Sadly I am about 1000km from the nearest decent garage! I live in an area where the average bush mechanic only has three tools, a larger hammer, a small hammer and a spare hammer in case he breaks the other 2. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted April 29, 2012 Share Posted April 29, 2012 we had this issue over on the LRO forum so might be worth a look over there. Cant do links because i'm using my phone at the minute. I'd have to say its an electrical issue because if your running at them temps i would expect the engine to of cooked its self by now. Quote Link to comment Share on other sites More sharing options...
Marks 110 Posted April 30, 2012 Share Posted April 30, 2012 One thing to try is to go on a run then leave the engine to cool completely (eg. overnight). Then slowly release the expansion tank cap in the morning. If there is a large hiss of air I would say the cooling system is over pressurising and the most likely cause is a faulty head gasket. You also mention your top hose split, another sign of excessive pressure? Another thought, can you actually feel the top and bottom radiator pipes are warm when the temp is showing 120 (proving there is actually flow through the rad). I wouldn't expect you'd be able to hold a rubber hose for long with 120 degree coolant flowing through it! I'll test the resistance of my gauge next time I go for a run. Mark Quote Link to comment Share on other sites More sharing options...
mrfish Posted April 30, 2012 Author Share Posted April 30, 2012 She does appear to be pressurising the expansion tank, so having to bite the bullet again and take of the head tommorow. Quote Link to comment Share on other sites More sharing options...
Marks 110 Posted April 30, 2012 Share Posted April 30, 2012 What engine is it by the way? Quote Link to comment Share on other sites More sharing options...
mrfish Posted May 5, 2012 Author Share Posted May 5, 2012 It's a 300 engine. As an update. The head was removed and there was no sign of any damage to the gasket, the mechanic reported that the bolts did not appear to be as tight as they should. However things then took a turn for the worse. The heater plugs were due replacement and I had a set of new lying around, unfortunatley when removing one of the plug it snapped and the remaining part just wouldn't budge. On the period of several hours lots of things were tried without success. Ended up with trying to drill and in the process the drill was not as straight as it should have been and resulted in damaging the head. So I am now trying to get a new head! One day I will get this car back on the road Quote Link to comment Share on other sites More sharing options...
Michele Posted May 5, 2012 Share Posted May 5, 2012 Quote Link to comment Share on other sites More sharing options...
Marks 110 Posted May 7, 2012 Share Posted May 7, 2012 Oh dear sorry to hear that. Had the problem with a broken glow plug myself but as the head was going to turner engineering for reconditioning they managed to remove it. I believe there is a special/technique but thats no help now! Just a thought could the head be repaired by a skilled aluminium welder and then skimmed? If not I believe there are new 300tdi heads still available which may be a better bet for long term reliability, that should be good for 250,000 miles or so. When I had similar symptoms on my 200tdi I found the head was slightly corroded around one of the coolant passageways this was causing the system to pressurise and the head gasket to blow. Even a re-skim didn't remove enough material to cure the problem so I had to source a good second hand head and have had no problems since. Would also recommend an elring head gasket and new head bolts. Maybe worth getting new/recon injectors at the very least have yours tested. I know this is going to be a relatively expensive job but done properly should last for years. Good luck and keep us posted. Quote Link to comment Share on other sites More sharing options...
mrfish Posted May 7, 2012 Author Share Posted May 7, 2012 Ok, temporary second hand head fitted (on loan from someone who is going to rebuild an engine) and all seems well, not overheating. Hoorah! So all i need to do now is get the new replacement head. Not sure which to buy though. I am looking at the performance head from Turner Engineering. Anyone fitted one of these? Is it worth the extra cash? Quote Link to comment Share on other sites More sharing options...
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