Getting My NA Ready for Summer...

[mikepellegrini]

It's been running kinda hot for the last couple summers - at least compared to my 951 - so I thought I'd be proactive and do some preventitive maintenance. Plus the thermostat's been stuck open for some time.

Another issue are the cooling fans. When the A/C and cooling fans are both running, the wiring gets HOT (temps as much as in the mid-140F range). I've heard old fans can draw more current, so I got a newer set of fans.

So I tore it all apart today. Here's the thermostat - it was stuck about half-open. Looks like the weld or whatever on one side broke.



My question then, is whether or not to replace the water pump?

I've put around 30K miles on the car, and the guy I got the car from put about 10K miles on it, so the pumps at least 40K miles old. It appears to be in good shape, - it spins just fine. But I'm leaning towards replacing it with a rebuilt from Pelican ($124).

Anyone have any experience from Pelican's rebuilds?

[djnolan]

If the belt was tensioned right I would hope for double to triple the miles you have on the pump. For safety, you may want to consider replacing some of the hoses, especially the upper, bypass, and heater hoses if they aren't fresh. These are the ones that get the hottest and crack soonest, since they return the hot coolant from the engine. Also try topping off the coolant with water wetter additive once you have her back together. This should make it run a couple ticks cooler by itself.

[djnolan]

And a new radiator cap to top it off!

[mikepellegrini]

I will try some water wetter when I put it back together.

Yeah. The problem is that the guy I bought the car from had no idea what work had been done to the car before he got it. The pump has 40K miles on it that I know of, but it could be a lot more.

I believe the engine is not the original - I'm guessing there could be 200-300K miles on the body, but that the engine is out of a much newer car - when I got the car, the compression was around 160 PSI straight across.

The pump is an updated version, so at least it's not the original one.

The hoses, aside from the long one that runs along the top of the radiator, are relatively new.

The problems:

The problem I had with the car, was that when it is hot out and you're in traffic, the temperature runs up around the half-way point or higher - occasionally going to the 3/4 mark.

My 951 runs much cooler - it hardly ever makes it to the 1/2 way point.

The NA has working A/C, but when you run the A/C the coolant temp goes even higher - it starts to run around the 3/4 point, and for me, that's just too damned hot! All of which means I can't run the A/C in traffic when it's hot - Catch 22...

The radiator checks out okay, I think. It takes the full blast of a garden hose easily. To check to see if it has any blockages, laying on its face, I filled it full of boiling water and then went over it with an infrared thermometer - no real big variations in temperature, generally (maybe 10*) although it was cooler around the outlet - but that makes sense, I think (because there would be a cooling effect as the water travels to the outlet, even without air being pulled through).

I blew the bugs out of it with a pressure washer.

I s'pose I'll still send it to a radiator place to be checked...

So I'm hoping the running hot was due to the stuck thermostat. That make sense?

The car is black, so you gotta have working A/C!

[djnolan]

The temp gauge runs up to 3/4 until the fan comes on at idle. This is normal at idle as the temp sender does not trigger the fan until it gets this warm, and it does not result in a lot of heat build-up in the engine. Once the fan finishes running or the car starts moving again it should shed the excess heat and return to normal. If it is not returning to normal temp after getting moving for a few miles, then there is a problem somewhere.

[mikepellegrini]

Like I said, my 951 runs cooler under the exact same conditions - it never gets above half (say 95C).

I'd like to have my NA run the same. It does cool down somewhat better when you're moving, but where the 951 will run at just over the 80C mark (almost always, no matter the ambient temp), the NA wants to go at around 97-100C or higher, especially if you have the A/C on. Sensors and Gauges - Information, Troubleshooting, and Testing

I know 100C is considered acceptable, but I'd just like it to run cooler.

Both cars have the mid-range thermofan switches (I think 75C).

[djnolan]

100C on the open road sounds high. It should run close to the rating of the thermostat when it is run on the road w/o the AC. It might go up a few ticks with the A/C on. If changing the thermostat doesn't correct this, suspects might be the gauge or sender or worse... Hopefully the problem was the busted stat was not opening fully.

(if you have a black car consider a white or gray dash mat to help keep the front cooler.)

[mikepellegrini]

The 100C is driving in stop and go, city traffic. On the freeway, it's usually a fair bit lower.

Hopefully the problem was the busted stat was not opening fully.

That could be. Hopefully. The way it sits right now, it's not quite half open. I'm not sure if it could open more, the way it's sitting, with the housing broken.

I think for the halibut, I'll heat it up in a pan of boiling water and see if it opens...

[mikepellegrini]

I boiled it and the thermostat did open quite a bit, bent housing and all. Not sure if it would qualify as all the way or not, and I'm not sure it would have worked as well when it was installed in the waterpump.

[Arizona_928]

Originally Posted by mikepellegrini

The NA has working A/C, but when you run the A/C the coolant temp goes even higher - it starts to run around hte 3/4 point, and for the, that's just too damned hot! All of which means I can't run the A/C in traffic when it's hot - Catch 22...

lol

Is there any play in the shaft/pulley of the waterpump? You should be good till the next timing belt change.

[mikepellegrini]

Originally Posted by AZ_porschekid

lol

Is there any play in the shaft/pulley of the waterpump? You should be good till the next timing belt change.

No, it feels like new. Nice and solid.

I just changed the belts around 1,000 miles ago - great planning...

[smokin_944]

Mike, at 27*C ambient temp, my early car runs at the first bar, sometimes a little more (80*C). The fan/s come on according to the temp value of the thermal switch, whatever that might be. Swap your thermostat to a lower value, mebbe 80*C and use a 75/70*C switch and everything should come out right. If it doesn't, you have a different cooling issue to contend with.

[mikepellegrini]

Originally Posted by smokin_944

Mike, at 27*C ambient temp, my early car runs at the first bar, sometimes a little more (80*C). The fan/s come on according to the temp value of the thermal switch, whatever that might be. Swap your thermostat to a lower value, mebbe 80*C and use a 75/70*C switch and everything should come out right. If it doesn't, you have a different cooling issue to contend with.

Thanks! That's what I ended up with - an 80C thermostat - ordered it here. My thermofan switch is a 75/70C.

I decided to go with my old waterpump. It is in great condition and it's not that big a deal to pull it off.