FrankthePostman Posted March 19, 2021 Share Posted March 19, 2021 (edited) Morning team. Changed the top hose on my 300tdi yesterday. Very straight forward. Didn’t do a bleed on the system though. Ran it with heater on after the hose change then checked coolant level after it had cooled and topped it up. Drove this morning and was overheating and the fuel gauge went up as well. Help. Edited March 19, 2021 by western Title changed to be more relevant to subject Quote Link to comment Share on other sites More sharing options...
western Posted March 19, 2021 Share Posted March 19, 2021 Could be a airlock, the fuel gauge is a seperate issue Quote Link to comment Share on other sites More sharing options...
FrankthePostman Posted March 19, 2021 Author Share Posted March 19, 2021 Top and bottom hose are both warm. Would that be a full bleed? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted March 19, 2021 Share Posted March 19, 2021 If both gauges are reading high all of a sudden it could be an earth fault. 2 Quote Link to comment Share on other sites More sharing options...
FrankthePostman Posted March 19, 2021 Author Share Posted March 19, 2021 Both gauges drop to normal when the engine is off. ? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted March 19, 2021 Share Posted March 19, 2021 Yes there's an earth point on the right side of the transfer box which certainly affected my gauges all of a sudden. You can see it if you look backwards into the front of the transfer box, it's high up on that left in that view. Certainly worth a clean and re-vaseline. Quote Link to comment Share on other sites More sharing options...
mmgemini Posted March 19, 2021 Share Posted March 19, 2021 There is a correct way to fill a 300Tdi coolong system. You don't appea to have followd that Quote Link to comment Share on other sites More sharing options...
Peaklander Posted March 19, 2021 Share Posted March 19, 2021 I doubt that would have affected the fuel gauge though. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted March 19, 2021 Share Posted March 19, 2021 I'd suspect a Dicky earth to the instruments. Either you disturbed it or it is just an unfortunate coincidence. Mo Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted March 20, 2021 Share Posted March 20, 2021 17 hours ago, Peaklander said: Yes there's an earth point on the right side of the transfer box which certainly affected my gauges all of a sudden. You can see it if you look backwards into the front of the transfer box, it's high up on that left in that view. Certainly worth a clean and re-vaseline. I think that this is what you are looking for: From memory, and mine's not great, the bolt right in the centre of the photo had a bare woven copper strap to the battery negative, although it does look as if there is an insulated earth cable on the bolt slightly lower and to the left. I can't remember where that went 🤔. Hope this helps. Mike Quote Link to comment Share on other sites More sharing options...
Peaklander Posted March 20, 2021 Share Posted March 20, 2021 No that’s not it. The one I’m referring to a small cable earth point. I posted a picture in another thread some time ago just not sure when or where. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted March 20, 2021 Share Posted March 20, 2021 My 300tdi temp gauge went up one day levels were fine, found the issue to be a combination of a bad earth as above also the push on green/blue wire on the rear of the thermostat housing was corroded. Pete Quote Link to comment Share on other sites More sharing options...
FrankthePostman Posted March 20, 2021 Author Share Posted March 20, 2021 It’s definitely the earth issue. The gauges only go up if I turn the headlights on. Haha. They then drop to normal when the lights are off. Just wont drive in the dark. Thankyou all. I’ll investigate further. Quote Link to comment Share on other sites More sharing options...
FrankthePostman Posted March 20, 2021 Author Share Posted March 20, 2021 Also, I’m guessing that this is the issue....... 2 Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted March 20, 2021 Share Posted March 20, 2021 That’s a fair bet yep 😊 Worth fixing sooner rather than later, it’s been known for the handbrake cable to act as a surrogate earth with melty results! 1 Quote Link to comment Share on other sites More sharing options...
uninformed Posted March 21, 2021 Share Posted March 21, 2021 Just a note: if it’s a 300Tdi Defender, turning the “heater” on does nothing to change the coolant flow. The coolant is flowing through the heater matrix 100% of the time (there are no valves/taps etc) Turning the “heater” on simply diverts air over the matrix via a crude flap operated by the cable lever. The heater matrix is however higher than the thermostat housing bleed and radiator fill point, hence why LR have the dicky bleed valve in the line to expansion tank. Bleeding the air out can be a bit of a bear sometimes. Quote Link to comment Share on other sites More sharing options...
FrankthePostman Posted March 22, 2021 Author Share Posted March 22, 2021 It was definitely the earth issue. All fixed now. Slightly bodged until I get the proper 50-10 cable lugs. Apparently they are like rocking horse ****. Quote Link to comment Share on other sites More sharing options...
Glue Posted March 23, 2021 Share Posted March 23, 2021 18 hours ago, FrankthePostman said: It was definitely the earth issue. All fixed now. Slightly bodged until I get the proper 50-10 cable lugs. Apparently they are like rocking horse ****. Good to hear you've got the issue sorted (or at least identified). The lugs shouldn't be too hard to get hold of, VWP carry them here, and I'm sure most other auto electrical suppliers will have them. It's probably easier / cheaper however to get in touch with your local electrical wholesaler. Quote Link to comment Share on other sites More sharing options...
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