How hot is too hot?

[robgagnon]

So you all might recall my blog entry about putting a 1987 4WD back on the road.

(http://www.toyotavantech.com/forum/entry.php?125-How-I-bought-a-1987-unrunning-for-7-years).

Anyhow, gee whiz, I actually drove the thing from San Francisco to Los Angeles yesterday, and it ran rather well. The items that need attention are slight pinging under significant load, so I likely have the timing too far advanced. And typically the temperature gauge would read close to the middle of the gauge at 70 MPH on a flat freeway. Is this about correct?

But going up the Grapevine (a mountain pass) the gauge got way up, not quite touching the little bit of red marking. Gee I hope I didn't damage the engine. It was rather warm for about 20 minutes. I downshifted to 4th and even third and was in the truck lane doing 45 MPH and I had the heater on full blast too. I still have the same amount of coolant in the system.

So I am of the opinion my clutch fan is shot. And that was the only extra part I forgot to bring with me, having an extra ECU, distributor, ignitor, and air flow meter with me!

So how hot is too hot in terms of engine damage? And is middle of the gauge for hours at a time about right?

[timsrv]

The factory gauges aren't all that accurate (that's why they don't have numbers on them). What's normal on one van isn't necessarily normal on another. Along with my working factory temp gauge, I also have an aftermarket gauge with numbers. On that van normal is about 3/8 on the factory gauge & that reads about 195 - 200 on the AM gauge. On a hot summer day while running AC and climbing a hill, I will allow mine to get as hot as 220 for short bursts. That rarely happens, but when it does the stock temp gauge is almost touching the red. Based on that, I'm guessing yours was probably below 220 deg F. In my opinion, 220 isn't hot enough to hurt anything, but I wouldn't want it to stay there for more than a few minutes. Tim

[robgagnon]

Thanks, Tim. Since I am driving into Mexico for six months, it seems prudent to add an AM gauge. Do you deem the temperature sender sufficiently accurate that you use that to drive the AM gauge as well?

Where did you mount the AM gauge, and is it digital or analog? Any other details on this addition?

It would seem to me that to cause any real damage a coolant system would need to boil over and loose fluid. That mountain pass is notorious for causing that: there are water sources along side the road for that reason and I think there is a sign suggesting drivers turn off the AC.

[timsrv]

My son's friend destroyed his car while going up that pass a couple years ago. My son was with him at the time and was stranded there for a few hrs. The Grapevine has claimed many vehicles.

Whatever gauge you choose will require a specific sending unit. The gauges with capillary type senders are typically too short for the van, so you'll want to choose an electric type. There is an extra port on the head that works well for adding a new sender. Here's a thread that shows where I and others have mounted AM gauges. Tim

http://www.toyotavantech.com/forum/showthread.php?307-Aftermarket-Tachometer-Install&highlight=gauges

PS: Just a quick search using the term "temperature gauge location" was all it took to find this thread. Lot's of info here & it's only a click away. If you don't like our search feature you can always do a Google search and simply add the terms "Toyota Van" or "Toyotavantech" to the subject terms.