Aragorn Posted September 16 Share Posted September 16 I'm having a hot starting issue with my Range Rover, but while diagnosing it i've reached a theoretical question that i'm not sure the answer to... Is a hot engine easier to start than a cold one? My initial thought, was that ofcourse a hot engine is easier to start.... But then with a bit more thinking i wondered if the heat would mean tighter clearances, pistons are going to expand, better ring seal, more compression etc etc... All the stuff that makes the engine easier to start, maybe actually makes it harder to crank? The issue at hand is that sometimes, when hot, the old 4.6 will barely crank over. You'll turn the key, everything will dim out, and you'll get a very slow crank or two, like a flat battery. Sometimes if you just try it a few times it'll go, other times hook up some jump leads, and it'll start. Except, the battery isnt flat? Its certainly not the healthiest battery, afterall its in a P38 and thus gets run flat far too often.... However it will always crank up from cold. And half the time it'll also start fine when hot. Its seemingly intermittent, and quite annoyingly so. Case in point yesterday, started fine in the morning, drove to the petrol station, also started fine, drove 90minutes of A roads, parked for about 20minutes, wouldnt start without a jump. Spent 2 hours offroad on forest tracks, started fine after ~30minute lunch, and also restarted fine another 3 times while stopping in the forest while waiting on people. So one failure in ~6 attempts. I'm sorta leaning towards replacing the starter motor itself, on the thinking that something weird is happening to it when its hot? The starter never sounds all that enthusiastic, so maybe its just on its way out... Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 16 Share Posted September 16 Yeah sounds like a weak starter or connections to it, it's right next to the exhaust so gets hot while running/sitting with heatsoak. 1 Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 16 Share Posted September 16 The fusebox tends to not like heat either, could be related to that. Try checking the ground strap from the battery to the body to the block as well. 1 Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 16 Author Share Posted September 16 Fusebox is a fair point, but since the starter seems to engage, i'm not sure it could be to blame? If it was a bad fuse box connection, wouldnt you expect no crank at all? I wonder if i can jumper the solenoid to the battery to test that possibility. Some of the cabling doesnt look the best. Theres a chunky ground directly from the battery to Alternator bolt though, then another (kinda carp looking one) from the engine block to chassis. I dont think theres anything from battery to chassis directly. Not sure i've seen anything from chassis to body either but i havent looked too closely. Maybe i should look to renew it all, a nice new cable right down to the starter and new grounds all round. Quote Link to comment Share on other sites More sharing options...
jeremy996 Posted September 16 Share Posted September 16 Always check the cheap stuff first - a jump lead between the starter body and the frame/battery is always a good diagnostic. Earth straps are cheap and not long lived. Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 16 Share Posted September 16 3 hours ago, Aragorn said: Fusebox is a fair point, but since the starter seems to engage, i'm not sure it could be to blame? If it was a bad fuse box connection, wouldnt you expect no crank at all? I wonder if i can jumper the solenoid to the battery to test that possibility. Some of the cabling doesnt look the best. Theres a chunky ground directly from the battery to Alternator bolt though, then another (kinda carp looking one) from the engine block to chassis. I dont think theres anything from battery to chassis directly. Not sure i've seen anything from chassis to body either but i havent looked too closely. Maybe i should look to renew it all, a nice new cable right down to the starter and new grounds all round. Indeed probably not the fuse box in that case. There should be a ground cable that comes off the battery, has a lug that goes to the body (between the battery and fusebox), and then goes on to the block by the alternator. I would make sure those connections are all good. Quote Link to comment Share on other sites More sharing options...
Escape Posted September 17 Share Posted September 17 Also have a good look at the connections to the battery terminals. Using jumpleads you take them out of the equation. The starter and everything else remains the same, so I wouldn't expect a jump to consistently cure a bad starter or problem in the fusebox/wiring (though more oomph can mask problems of course). Quote Link to comment Share on other sites More sharing options...
Alsace_rangie Posted September 24 Share Posted September 24 I had an intermittent starter problem i.e. sometime just wouldn't turn (post in the Disco section). Found out one of the brushes was stuck. Failure was not related to engine heat though. Quote Link to comment Share on other sites More sharing options...
fmmv Posted September 25 Share Posted September 25 If you can reasonably readily reproduce the problem you can check with a meter, one lead on battery negative, what the voltage is on the battery +ve, engine block, starter terminals etc. Ideally it will all read either pretty much zero or same as the battery +ve. If so that would point to the starter. Quote Link to comment Share on other sites More sharing options...
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