Alternator issues?

[Heaumey]

when arriving home in the wagon last Sunday I noticed a strong burning smell, lifted the bonnet to find smoke coming from the alternator. Immediately disconnected the batteries and left to cool. Once cold enough to touch removed the alternator to find a molten mess.
Have only had time today to have a look over it. I have replaced the alternator (genuine unit), replaced both batteries as they were mismatched and an unknown age, checked and cleaned all earths, checked that the intake heater relay shuts off after 60 seconds. Have taken it for a run but the alternator is still to hot to touch, so it’s now sat outside with the batteries disconnected. Any ideas??? Could an issue with the engine intake heater cause this??? My plan for tomorrow is to isolate it and try again.

 

[uHu]

The intake heater can have an internal short which makes it take even more power than it's already huge consumption. It is not fused, but some models (depending on year and market) have fat fusible link, so it can really go to town with battery juice.
Nother issue is that the intake heater is an absolutely useless waste, and a real killer for battery and alternator longevity. There is no use for it whatsoever.
Don't know if this has anything to do with your issue, but it would be worth your while to disconnect it. Sometimes a relay (like the intake heater relay) can get stuck closed, which would really generate some heat.

 

[Heaumey]

The intake heater can have an internal short which makes it take even more power than it's already huge consumption. It is not fused, but some models (depending on year and market) have fat fusible link, so it can really go to town with battery juice.
Nother issue is that the intake heater is an absolutely useless waste, and a real killer for battery and alternator longevity. There is no use for it whatsoever.
Don't know if this has anything to do with your issue, but it would be worth your while to disconnect it. Sometimes a relay (like the intake heater relay) can get stuck closed, which would really generate some heat.

Thanks uhu, that confirms my thoughts. Will disconnect tomorrow and try again, it may be intermittent as when tested with a multi metre it seems to operate correctly.

 

[Heaumey]

Okay, heater disconnected. Been for a long run with everything on, lights heated seats etc. My laser thermometer gun says the housing is about 60degrees, still feels a bit hotter than happy with. Thoughts??

 

[uHu]

60 deg C on the alternator? Doesn't sound high, although I've never measured. It is, after all, mounted onto a hot engine, AND producing the electric power for all the consumers.

 

[Chris]

Been for a long run? Where? Don't you go putting unnecessary miles on my truck fella.

 

[Heaumey]

Been for a long run? Where? Don't you go putting unnecessary miles on my truck fella.

Well when I say long......around the island twice, about 20 mls

 

[StarCruiser]

60c doesn’t sound at all bad. What was it reading before you disconnected the intake heater?

 

[Heaumey]

60c doesn’t sound at all bad. What was it reading before you disconnected the intake heater?

I didn’t check it, you can only place your hand on it for a second it’s that hot. I’ve never really payed this any attention before, it could be correct but the fact the last alternator went up in smoke I’m just a bit conscious. Just as a bit of a pointless test I crawled under my transit when I got home today and you can comfortably hold that one, I know it’s a bit like chalk and cheese but I’m at a bit of a loss.

 

[StarCruiser]

I must say I’ve not monitored the temp of any vehicle alternator and as an ‘open machine’ I would expect it to have plenty of cooling. 60c is not uncommon for electric motors so it should survive but if others are experiencing lower temps on the exact same vehicle (I’m thinking ambient temp causing a rise here) then there may be other issues. I would expect if there were a short circuit somewhere that you would soon know about it, and the batteries would discharge very quickly.

What really we’d to be done here to give you any confidence at all is to check current from the alternator, and voltage at the battery terminals. If these are within spec then all should be well. While you’re at it check the currants on all outgoing wires from the battery. You will need a DC clamp meter to do this. It’s a bit specialised, but a very useful piece of kit. If you haven’t got one try and borrow one.

 

[Heaumey]

I think I’ve now got an alternator fetish, every time I see one I have to have a fumble.
Not happy with it so will investigate further at the weekend.

 

[Heaumey]

Update, due to having no free time at the mo I cheated and booked the truck into our local auto elec shop. They had it for a day and reported back that all is normal with no issues found, they have put the issue down to just the old alternator failed and are not concerned by how hot the replacement runs whilst everything is on. So unless I can find another to compare it to that’s where I’m at.....hopefully not to be continued!

 

[Heaumey]

Having now used it for a while whilst monitoring this issue I’m not convinced, seems I can drive nice and easy for any distance with everything on and all is well. But as soon as you get on the throttle or push it up a hill the alternator temperature gets to a point where you would burn yourself if you held it, now thinking of a possible blocked cat?? Or am I missing a heat shield?? Has anyone ever been near there alternator after a hard run just for comparison..... starting to regret selling the 80!!

 

[Towpack]

I’ve been investigating my alternator recently due to potential charging issues and found it quite hot to the touch when adjusting the belts and cleaning the connectors etc. Not too hot to hold your hand on it but this was after relatively short runs round town. When the engine it hot enough for the fan to engage the extra heat from the engine bay is immediately obvious and probably would make the alternator itself much hotter. This is on an 80 series.

 

[Heaumey]

Thanks towpack, I know the alternator is tucked up under the exhaust manifold so obviously it’s going to get warm just from it’s position but this seems to hot to be normal. Do you have a heat shield on the alternator or above?

 

[SteveJB]

I have removed the plastic splash guards from under the front wings and running full bash plates front to end of gearbox when the engine has been working hard after towing heavy trailer there is a huge amount of heat coming from under front wings as spash guards are held on with push studs easy to remove and replace may help improve airflow through engine bay

 

[Heaumey]

I currently have the drivers side splash guard off which is where I am monitoring the alternator temperature from, after researching this on mud and some Facebook pages it seems some fit a pipe behind the grill to direct air to that area. Worth a try? Anybody else ever heard of this?

 

[Heaumey]

Back to this issue today!!! Can any other hundie owners out there confirm if they have a heat shield bolted to the alternator or directly above??? Also can you comfortably touch it after a long run??? I’ve never not been able to diagnose an issue, but with no other identical trucks that I know of over here I think I’ve been beaten on this one.

 

[Indie]

I have a 2001 100 ill have a look tomorrow and let you know..

 

[Heaumey]

Indie, you’re a star.