starter motor heat soak - hard to start when hot

[Mr Blue]

Sup!

This is my 2nd starter motor that has had issues with starting when the engine is hot. It was fine for a while but now does what my old one did. All cable voltages checked.

These mk2's stall often and can be scarey in traffic when I know it wont turn over easy if i stall 

Has anyone else got this heat soak problem and any way of shelding the new motor from heat?



Blue

[X4MGS]

I've read something about this problem before - but for the life of me I can't remember what the guy did to solve it...

I seem to think he either wrapped a heat shield around it or bought a better quality starter...

[bodga]

I had this problem, i made it a lot better by doubling up or fitting thicker cables from starter to battery and battery to chassis etc. Cables removed from mk3 golf and polo at local scrappy I also cleaned all connections and smeared with high temp grease.

It still struggles to turn over when hot but i put this down to the battery, from memory its an 065 which i think is a tad small for a 16v. I  think it should be an 075

[nrm69]

I have the same problem and have followed some of the advice to cure it without total success.

Not sure what engine you have but be very wary of Haynes when removing the starter motor, if it is at the front of the engine bay then the bolts for the starter motor also pass through the engine mount, brown trouser moment when the engine starts to drop.  Get a trolley jack to take the weight.

There is a small copper bush in the gearbox casing which the shaft of the starter motor goes into and a lot of people recommend changing this first, only a few quid from VW and the new bush should let the starter spin more freely.  You need a suitable tool to remove the old bush, another brown trouser moment when you chew up the old bush with a suitable sized tap but can't get the thing out!  Just persevere and it will come out, perhaps in small pieces.

Another recommendation was to upgrade the cables from battery to starter motor, alternator and earth with those taken from a Mk3, cost me £1 each from the local scrappy.

If you buy a new starter motor check that it is correctly rated for your engine as various outputs are available, no point buying one that will struggle to turn it over even when new.  If necessary check if there are connections on the solenoid for the cold start system.

I'm sure that this subject has been covered several times here, search for hot starting problems and you'll find various threads which is how I found most of this out.

[clipperjay]

I think something is burning them out?
Too hot might mean there is current still going through the unit even after you cranked it.
I would be tempted to stick a volt meter on it to check for any current still on it?
After all these years heat soak breaking a starter I just dont buy it either electrical fault or just cheap nasty starter?
 

[Mr Blue]

Thanks for the replys all.

I think it's the starter itself as all the wires and volts/amps have been tested. This only happens when its hot.

I got a high cranking battery with a 90A alternator so its getting charged well.

It must be the heat from the radiator as its right next to it. Its the 2nd time this has happend and I replaced it with a recon one. just dont want the new one to do the same.

Will change that bush and hopefuly break a perfectly good mk3 just for the starter cable 

[danny_p]

good plan that.

[Oet]

i am really glad you posted this thread as i have the same problem with my valver when it warm, it wont crank.

I have been meaning to do something about it, but lost the info i 'found' online ages ago with the fix on what to do. Apparently there is a diesel starter we can fit instead (i think its possibly a mk3 one) that will stand up to the heat that the gearbox and engine create thats stopping ours turning over when warm, its not they are faulty, its just everything swells slightly when its warm stopping free movement of the starter.

hopefully someone on here will know...

[clipperjay]

You have to confirm this, but I've heard the MK3 diesel a 1.6 TD might fit, but the spade connectors are different one is bigger or smaller, but the idea is as its a 1.6 Mk3 starter will be more powerfull due to the compresion it needs to crank so in theory its got more cranking power than a stock 16V, 8V might be different aswell, but its the gear box codes that count 020 will 020a won't ?
A MK3 16v or TDi one won't I think its becuase its a 020a gearbox?
Also a MK2 GTD starter would work but imagine they are scarce on the ground?

[Oet]

that sounds very familiar, nice one dude, yes i remember there are quite a few we cant use due to the different gearbox, but the 1.6d sounds right, i also remember something about having to do something with one of the terminals.