Transaxle/engine oil temp vs water temp

John Fitzpatrick · 11-25-06, 09:13 PM

With the discussions going on concerning oil temp and the best location for the sender, and engine temps in general, I realized I really don’t know what the real value of monitoring both engine oil and water temp. is. Given limited dash real estate, (and the difficulty of scanning mutiple instruments while very busy) would it be a better strategy to switch the oil temp sender over to the transaxle and keep an eye on water temp for engine concerns and transaxle oil temp for that gauge? My gauges aren’t electric, so a oil temp selector switch isn’t an option.

John Fitzpatrick · 11-28-06, 12:32 PM

I'm going to assume this was one of those dumb questions that everyone but me knows the answer to. Sadly, it wouldn't be the first time! Perhaps someone could provide a link to a site that goes into the advantages of monitoring water vs oil temps? I'll post a question on whether monitoring tranaxle temp is worthwhile on that forum.
Thanks,
John

Lynn · 11-28-06, 01:04 PM

John,

If I had to monitor one and not the other, I'd go for the water temp as it is probably the first temp that will go out of range and will do so with a variety of root causes. Any of these would be adequate provocation to shut down and determine exactly what is going on.

Regards,
Lynn

Russ Noble · 11-28-06, 01:08 PM

I think the answer is..... It depends!

What are you using the car for? Road only, short races, long races.

Probably comes down to personal preference. Road only and short races I would say it doesn't matter. For long races I would have both. Also what transaxle/engine combo are you running? If you are right on the upper limit of the transaxle capability I would definitely monitor trans temp.

That should get the ball rolling. Now everyone can tell us why I'm wrong!!!

Cheers

Lynn, you posted while I was typing but I don't think John was talking about eliminating the water temp, I think he was trying to decide between engine oil and transaxle temp.

since the oil condition is already monitored to a degree by the pressure, I would go for trans temp.

Ian Anderson · 11-28-06, 04:37 PM

What about some of the current gauges that use 2 needles and show 2 different elements e.g. water temp and oi; pressure, oil temp and oil pressure etc.

http://www.rallydesign.co.uk/catalog...oducts_id=3780

Should give you an idea of what I've seen

Ian

John Fitzpatrick · 11-28-06, 06:02 PM

Russ-
The transaxle is a ZF 5DS 25-2 and the engine is a 289hp, roughly 400 BHP- don't know how close to the edge that is. I'm restoring the car, but since I won't be able to drive it, I can't be sure how it will be used once it's done and sold. As a vintage race car, I'd expect medium distances in the 250 mile range, although Lotus did enter it in the BOAC 500 once in the late 60s (DNF)
It sounds like the consensus is to go with engine water and transaxle oil temps.- I'm assuming that an internal engine problem registers quickest on the oil temp while the water temp would catch a broken fan belt or water leak first, engine problems later. That close?
Ian-
the twin guage is a good idea, but I've got the vintage chrome bezel Smiths, and I'd like to keep the look consistent.
Thanks, gentlemen
John