Oil Causing overheating

[AE86less]

While I was at pick a part the other day I ran into a guy I met at Suprafest 09 (who's name I have embarrasingly forgotten), Christo's stepson. We got to talking about some stuff and he mentioned that if the oilpickup in the sump is blocked it can cause overheating.

I want to know if that might be the case with my GX71.

When I bought it and did the first oil change it came out the consistancy of half melted icecream. Immediately after changing it the engine started making tappety noises on cold startups that would go away as it heated up/made oil less viscous. This lead me to believe that the flushing oil I also put through must have dislodged a whole bunch of crap and it got caught up in the pickup?

Either way, when I drive at sustained high speed (95km+) the car slowly overheats (also overheats faster on hills etc), then cools down while coasting at idle. Could this be caused by not enough oil circulating under load? I have already run a chemical flush through the coolant system, it's had a new WP, it has good coolant in it and isn't using water.

Cheers

[sergei]

I am NOT MAGN1T , but I will say you might have a case of BHG.

While engines benefit from oil cooling, oil itself does not have enough capacity to account for overheating that you are describing, low oil flow leads to more serious problems than overheating (and it does not cause overheating).

There is possibility that the engine is stuffed on multiple levels (worn bearings, blown head gasket, sludge) from what you are describing.

Is it 1GFE? They are relatively cheap, probably cheaper to scrap the engine and get a new s/h one (if it is sludged and has bhg).

Do a compression check. Remove the valve cover and have a look for black/brown plastic like sludge inside. If you have it, just get new engine. You cannot flush that stuff without disassembly.

[AE86less]

Thank god you aren't MAGN1T Cheers Sergei, you pretty much answered it.

The engine is 1G-EU with 267 000kms and an estimated 70-80 Fast and furious horsepowers!

I was asking more out of curiosity, I know that the engine is on the way out, it blows oil smoke and is seriously slow (I got dragged by a bus ). I'm currently working on rebuilding a new 1GGTE.

[CAMB01]

Have you checked and/or replaced the thermostat?

[TRD_ZERO]

i had the exact same issue a few weeks ago and i tried everything to fix it, changed hg, thermostat and evrything i could think of. It was due to the radiator being blocked. Give it a flush.

[Anth_555]

try changing to electric fans. had the same problem with mine and that fixed it. they have been known to do that or so i was told

[MAGN1T]

i had the exact same issue a few weeks ago and i tried everything to fix it, changed hg, thermostat and evrything i could think of. It was due to the radiator being blocked. Give it a flush.

Radiators only ever block up when you add water instead of antifreeze. You're adding water because you're loosing it.
Water plus exhaust gasses from leaking HG plus aluminium heads/iron block cause sludge. Radiator blocks.....easy.
It's called chemistry.

Steve

[Crucible]

Radiators only ever block up when you add water instead of antifreeze.

Steve

Have seen radiators 70% blocked when using antifreeze.

[frost]

those turbo rover tomcat things block up real easy, even with antifreeze in prime condition,

[Crucible]

those turbo rover tomcat things block up real easy, even with antifreeze in prime condition,

euros are the worst.

[RS13]

Sounds like a blocked radiator, given that you aren't using water and you've already replaced the waterpump. I've come across this symptom a few times before (long distance/sustained rpm causing overheating which cools when idling), turns out the radiator is so blocked that it would be only 30% efficient, which is fine at idle, but not at cruise speed.

Adding radiator fans will only help if your viscous unit on your current engine-driven fan is poked, besides, if your radiator is blocked, adding fans won't do anything anyway!

those turbo rover tomcat things block up real easy, even with antifreeze in prime condition,

Lol, those things are rubbish! even just looking at them the wrong way could cause a BHG, blocked radiator, broken clutch, cracked head.. lol.

[frost]

Lol, those things are rubbish! even just looking at them the wrong way could cause a BHG, blocked radiator, broken clutch, cracked head.. lol.

no no no you got it all wrong, it goes.. blocked radiator, BHG, cracked head, broken clutch,

though i must say its still not as bad as the MG's with the foot long head studs,

Could this be caused by not enough oil circulating under load? I have already run a chemical flush through the coolant system, it's had a new WP, it has good coolant in it and isn't using water.

Cheers

dont think it will be oil related, the chemical flush might of made it worse,
how did you do the flush? take the whole rad out?
it might of just loosened some crap that would block your system up more,
real way to do it is get the radiator roded(sp)

[matt dunn]

Yeah the only real way to clean a radiator out properly,

is to remove it and get the tanks taken off and done properly.

[TRD_ZERO]

I just replaced the radiator with a spare i had leftover from my project. Fixed instantly so that was obviously the problem. Couldnt you just buy some radiator flush stuff that you run for awhile or something and drain it?

[matt dunn]

All Radiator flush ever seems to do is flush all the crap out of the engine cooling system into the radiator to block it,


same with all the stop leak type stuff, blocks up radiators.

[Crucible]

Yeah the only real way to clean a radiator out properly,

is to remove it and get the tanks taken off and done properly.

yes very true, backflushing is ok for general maintenance/coolant change, but it wont remove build up in the core.

Tanks off and rodding the core is the only way, chemical flushes are a waste of time.

If a car comes in with overheating issues I check in this order.
1/ TK check
2/ Pressure check
3/ Flow check, hoses hot and fans are cycling etc
4/ thermostat
5/ Radiator out and rodded
6/ Waterpump out (corroded Inpeller)