David Trimble

Ok- I just switched my '84 T/A that had the factory HO option from the clutch fan back to it's original electric fan option (with a slightly cooler fan switch). When it had the clutch fan it ran around 170 degrees constant. Now with the electric fan it's peaking around 225-230 (and that's if the temp gauge accuracy is to be believed....)

I have noticed that now the car's developed a starting problem - if the engine sits for a few minutes and heat-soaks up to above 235, the starter can crank the engine but it's definately having trouble turning it over. Now I've replaced the starter about a year or two ago and before the fan conversion I had noticed that cranking the engine hot or cold the starter sounds like it's slightly hesitating during cranking. That is, it's not turning at a consistant speed but sounds like it momentarily slacks off once in a while..... the battery's fairly new too (about a year old)....

My question- could it be that I've got some defect in the starter that's causing the bad cranking under high heat conditions that wasn't as apparent when the engine ran cooler? Or is it something else that would cause this?

Thanks!

Danno

It's called "heat soak". Typically it is caused by the starter simply getting gummed up with crap. Many times all you need to do is take it apart, clean it and relube as required. You can get a heat sheild for it, many guy's like it and it will prolong the life to some extent. Unless you have headers where the starter may be subjected to extreme heat it always can be traced to the starter itself. One thing I have found by experience is that todays reman units are being loaded with offshore internal junk for replacement parts. Stick to an AC Delco reman, they are a few more bucks but worth it.

David Trimble

Right- I don't have headers, but the starter being pretty close to the block it probably doesn't take much to heat it up. It may've been barely surviving under cooler conditions but my raising the temp that much probably sends what defect it has over the edge. While it's still pretty clean, I'm sure you're right in that the starter's probably got a lot of offshore junk in it.

I'll look into a AC/Delco- or if I still have it around, I might just rebuild the original starter.....

BTW, before I swapped to the electric fan, when I've had the clutch fan in the engine I've seen fairly consistent temperatures during operation. With the electric fan in place I'm seeing a wider and faster variation in temp- is this normal for a electric fan setup?

Danno

Yes, the operating temp won't be anywhere as stable as with a belt driven fan. My 89 has a dual fan setup operating at stock specs. Primary fan let the engine get to about 225 degrees before it kicks in, aux is around 234. Any modern car no matter who makes it if it has electric fans they allow about a 20 degree rise over stat temp before the fan cycles. If the fan temp is close to the stat temp the fans would constantly cycle on and off putting stress on the alt, fan motor and relay.

David Trimble

So seeing temps maxing out at 225-235* won't be harmful to the engine, it's when it hits 260 and can't cool down is when I should be worried, right?

BTW would cooling system pressures would be about the same with either clutch or electric fan systems (I've got a 15psi radiator cap)? Since the engine hasn't been rebuilt (yet) I'm also wondering if any of the gaskets associated with the cooling system would be ok....

David

Danno

15psi cap is standard on any GM car out there today regardless of fan operating method. Don't forget that when you shut off the car after it's at operating temp you get a significant rise before it cools down anyway. If gaskets have been ok up to now chances are you will have no problems whatsoever.