Hey everyone, this past weekend I successfully revived my FD after sitting garaged for five years. Since it is now running, I need to troubleshoot my temp issue I was having/troubleshooting five years ago.

After reading several threads about common cooling issues/solutions, I realized that I am currently running at 100% coolant whereas most recommend 50/50 or more water than coolant.

The issue is my temp consistently climbs and I generally cut the engine at around 220F to avoid issues. My temp values are based on my digital temp gauge not the stock temp gauge which never seems to rise above 50%.

Could my issue be as simple as removing coolant and adding water for the 50/50 mixture? Would this be a good place to start?

There are also currently no signs of any cooling system leaks and I am running a stock radiator. I also replaced the thermostat which didn't seat perfectly but fit.

Thanks as always!

 

Yes you really shouldn't be running that much coolant. The coolant is only there to stop the water from freezing it doesn't actually cool down the engine. The water is what transfers the heat.

Also make sure that your fans are running properly.

 

first i always run 5% water wetter or purple ice in my cooling system

next, coolant does a couple things and is actually can be thought of an active ingredient to the water in your cooling system, your coolant modifies the water in the system to not freeze over and work to not to exceed a certain temperature as well. That is also why flushing coolant systems when weather changes are important because coolant turns into a no longer working ingredient and its useful life depletes.

also remember if you dont have an upgraded radiator i would highly recommend, and if you dont you better be running the factory undersweep. i have seen rotaries that have lost their undersweep over time and they will overheat until it is replaced and/or radiator is upgraded.

those are a couple of key items.

Good luck with the diagnosis!

 

In stock configuration, the fans don't come on low until 221F. For a mostly stock car, getting to 220F during the summer won't be uncommon.

 

Fans will come on earlier if the A/C is switched on. Are you sure you got all the air out of the system?

 

As well as other higher draining electrical loads (such as the parking lights). However, I didn't plan to go into every tiny variation to get a point across.

 

surprised no one asked this... where are you getting your temp readings from? (location of sensor) since youre not reading it off the stock...

 

50/50 mix is always what you should run. Water cools far better than antifreeze, the antifreeze is mainly there for it's non-corrosive, lubricating, and freeze point lowering.

Straight water cools great but is ROUGH on the engine, easy way to corrode the engine internals over time and kill a water seal.

I also agree with Mahjik, make sure your fan control system is doing better than stock, minimum upgrade to an FC thermostat.

Dale

 

Great information here! Thank you all for your feedback. Unfortunately, five years has passed and there is no longer any 3rd gen mechanics in my area so I am on my own. Truth be told I would rather learn it all myself anyway.

Sounds like a coolant flush and 50/50 fill will be the best place to start my troubleshooting. Also, I am glad someone mentioned the undersweep for the stock radiator. Mine is still there but not in very good shape so that may be somewhat contributing to my issue.

If I replaced my stock radiator with an aftermarket (fluidline or Koyo), can I remove the undersweep completely?

Is there an easy way to test the fans/force them on without pushing my temps to the limit? I am not comfortable running my car at 220f and above? Can I lower the threshold?

As always this site has once again proved to be a great resource, thanks again all!

 

even with a koyo/fluidine people will still highly recommend using an under tray...

i run ~70/30 water to coolant..


whats water wetter? sounds familiar but i dont recall what it is....

 

It's an additive that purports to drastically improve the cooling capabilities of water/coolant mixes.

aka snake oil

 

^ I'm with muibubbles on this one. 70 water to 30 percent coolant gives you optimum cooling, yet good lubrication and protection from overtemp and internal corrosion. If you run straight distilled water with water wetter you risk internal corrosion. More conservative, i.e., 50/50 and your giving up some cooling capability, IMO. It also helps to change it on a regular basis, i.e., annually if possible.

 

+1. . .50/50 is a mixture set for -45 celcius. . .i wouldn't mix this unless you're driving this in the winter. I run water with a little water wetter, as most of my friends and customers do. . .with no problems...