Hey,

Not sure if this is normal or not but yesterday [~85deg out] on a drive with a bunch of other RX-7s my temp spiked to ~60% of the gauge while going up a 10degree hill for a couple minutes. WOT and topping out 2nd/3rd gears.

A little earlier on the cruise, I noticed the temp up to ~40% after a bit of hard driving and twice when I hit 7100RPMs the car missed a little. Normally it runs smooth right up to 7500RPMs [shift point].

It's an 87' base model with a rebuild ~30k ago: ~140k housings, original rotors/plates/eshaft, new atkins hard/soft seals and springs, assembled according to the atkins DVD [My first engine build].

Coolant was changed out a few months ago [and I ran a flush through the system].

Oil was changed out the night before the cruise: 4qts Castrol GTX 10W-40, 1.5qts Chevron 20W-50, and a WIX filter.

Exhaust is a Racing Beat streetable header, RB presilencer, and an excellent condition original catback.
Intake is a generic K&N style cone filter.

The engine has all stock ports and questionable 5/6th activation [I still haven't checked if they're working or not.. The RB presilencer does have the pickup line for the split air pipe, but you know how these things are..]

Any ideas? Or does this seem pretty normal?

 

man, you where raggin that car out. you where going up hill, in 85 degree heat, and topping out 2nd and 3rd.


what did you expect would happen?

 

What the heck is 60% and 40 %?.is that the Position on the stock Gauge?.
get a real Gauge..(temp Gauge).That way you can See temperatures,and not look at what is In My Opinion a "modified Clock".(the stock gauge).
Other than That,.The car sounds like it is running Ok,

 

the stock s4 gauge has a linear sweep at least. It's not "buffered" like the s5 gauge, and it is not a useless gauge. I've compared it to readings on my Power FC taken from a brand new OEM water thermosensor (on the waterpump housing). The needle on the factory gauge doesn't always correspond to the same temperatures... half way up one day isn't the exact same temperature as half way up the next day, if ambient conditions have changed. Still, your engine probably is running hotter than it would be with everything working in "like-new" capacity.

From my experience, halfway up is usually around 100C/212F. So you may have gotten as hot as 105C/220F, which is nothing to panic about but still hotter than you would like. Assuming there isn't a major blockage in the radiator or oil cooler, I think you should try replacing the thermostat with a new OEM one. It could be sticking. I remember when I picked up my s4 n/a car 6 years ago I also noticed the gauge going over halfway. I changed the thermostat and it made a noticeable difference even on the factory gauge.

 

SirCygnus>> lol... Well usually I don't drive it half that hard, so I really didn't know..

Misterstyx69>> Yea, position on the stock gauge. Money's a bit tight [unemployed] and I don't think I'd need it often enough to buy an accurate gauge.

Arghx>> A couple of notes I forgot that could be relevant: When I changed the coolant I had changed out the water pump [the gasket was bad and it was a bit rusty, so I got a lifetime warranty pump from Shucks]. Also the thermostat was a new Mazda unit installed when the engine was being rebuilt [the original build had some cheap one]. Do you think it could've gone bad after 3 years? The coolant was changed just a few months more than 2 years before the recent change.

Normally the gauge is in the 29% to 39% range. [if it's cold out hot out - if it's average out then it's right on at 33%] But I normally don't go WOT topping out gears uphill.

 

I'm personally not too familiar with where the temp should be sitting as per normal myself. Marc keeps telling me that my car is overheating. It sits at about 51% all the time. Anyway, as for the money bit, I apologize for the delays. My situation went from swell to terrible very quickly. Anyway, I'm going to drop some cash with Marc before work Tuesday morning.

 

John>> Your car's an S5 so it should be right in the middle. I'm told that if it moves up at all on an S5 [once it's warm] it's a bad sign.. [Though 1%.. That's probably hard to tell?]

Ok sounds good on the money [Though you should probably facebook or PM that stuff ^_-]

 

For one you have no actual idea of the danger you could be in if you don't know what the actual temperature is. The stock gauge is very inaccurate. Second, yes a thermostat could be bad if it was in there for 3+ years. Also my car used to heat up a little (190-210) beating on it going uphill or just prolonged beating, but it never overheated. Now with my Koyo I never see much above 178.

 

@ OP

how is your radiator? new? or stock unit?

 

1SWEET7>> Ok, I'll look into changing the thermostat pretty soon.

duo2999>> It's the original automatic radiator [I converted the car to a manual last summer]. ~199K on the radiator. I don't think it was particularly dirty when I swapped the engine, but I haven't checked the fins since.