high temps after parking
 

So my car keeps a nice steady 85 degrees C water temp, maybe up to 92-95 in traffic. But after parking and turning off the car, my PowerFC commander shows it shooting up past 111 and sometimes 115 degrees! After opening the hood I can hear all kinds of boiling and expanding metal sounds. These numbers would be very high so I am wondering if this is normal and if not, what can be done to remedy it? I have not had any issues with it but it seems this kind of heat would reduce the life of many parts.

I do have a turbo timer but usually don't let it sit and idle for more than 30 seconds or so.

sounds like you have quite a bit of air in your coolant. You need to "burp" it out. Try unhooking the throttle body coolant line at the rear of the engine and have someone hold it up while you add coolant to the rad filler neck. Squeeze the lower rad hose while filling to get as much air out as you can. Only do this when the car is fully cooled off. Do this, drive it, let it cool off, then do it again. even a third time doesn't hurt.

If you're having the same problem after this, one of your rad caps may be faulty. It wouldn't hurt just to replace these anyways however.

If after burping AND replacing the caps the problem persists, you should try to delete the air separator tank. A simply 40$ piece from any mazda dealership pretty much does this job.

Hope this helps

Def burp the system to be safe although if the temps are steady during driving then maybe it is fine but I would do it anyway.

Btw its completely normal for temps to rise after shutdown. Its called heatsoak. Depending how high ambient temps are and how aggressive you were driving will determine how high the temp will go when the car is shut off.

What are the ambient temps when this happens?

When it is hot out (85 degrees) mine goes up high like that as well. Thats why some people open their hoods when they finish their drive.



John

^Agreed. The coolant in the area of the temp sensor stops circulating, but it continues to soak up the heat from the surrounding metal. That's why your indicated temperature rises.

Boiling sounds aren't unusual and usually a sign that some air is in the system.

High temps are normal after shutdown. If you have a garage, prop open your hood when you park it. This will help the engine cool, and will extend the life of many plastic/rubber parts under the hood.

Agree with the heatsoak, I have even gone to having set a house fan blowing cool air over the engine bay after poping the hood during the summers here in Arizona once back home in the garage. On club drives it is a ritual for the FD's to open hoods on stops. Temps climb when stopped but once started again fans turn on and water gets circulated they go back down to normal. If it gets too hot the fans should stay on even when shut down, thinking that was a recall item if memory serves me and don't remember the temperature that trigers that. Since having gone single with v-mount and other things I can't remember last time it happened other than still had twins and other stock clutter in the engine bay.

Yeah heat soak is expected but not that much of it. I also run a steady 85C (unless it's really hot outside) and my cars temps aftershut down rise at the most to 105C. I also say to make sure to burp your coolant properly.

I remember some people back in the day talking about a similar mod that lets the fans on for a few minutes after shut down. To be honest, it never made any sense to me because there is no real benefits in letting the fans run with the water pump off. Basically, all that it is doing is cooling the coolant inside the radiator only, but the worst part is that its blowing hot air into the engine bay lol.

It's bad heat soak. Run your turbo timer for a minute, and try to take it easy for the last 5 minutes of driving.

Also, turning on your runing lights and AC will turn on the fans. That's what I do without a turbo timer in the Bay Area and it works well. I rarely boil the coolant.

Look into a leslie funnel from summit racing it makes burping the coolant easy. There is a write up on here about it and how to burp the system with it.

Things that will help lower those temps:

Leslie funnel to properly burp the system
Evans Coolant!!!!!
Dual Oil coolers if you don't have them
If you have a PFC you can actually set your cooling fans to come on sooner
AST delete is good..but won't really do much for lowering temps..just makes the system a little more reliable and easier to work with with coolant changes etc.
a vented hood
V-mount IC set up will work great here in Ca..just make sure its ducted correctly.


Here in CA....especially out where I live..I would see 105-112C on a regular basis in the summer and hot days. It's no fun..especially out on the track.

You probably don't have air in your system. I've heard plenty of turbo cars boil coolant after shut down. A 50/50 mix of ethylene glycol and water boils at 225 F or 107 C. Cast iron turbo manifolds don't help.

Funny seeing this thread now. It is 25 F outside and boiling is the last thing on my mind.

My single runs 85*C in 90*F outside temps. These are the steps I do every time I drive .
1. Don't run it hard, then park it.
Take it easy for 5 minutes or so before you stop, then let it idle for a little, then turn it off.
2. Switch the key to "On", but do not start the engine, so the fans come on.
Do not do this if the battery is weak. Turn off radio and such.
3. Open the hood.
4. When the temps on the PFC reach 95-97*C, start the engine and let it cool,
it should go down to 75-78*C, or lower. When the temps stop falling turn it off.
5. If it's really hot outside, you will have to repeat step #2 again.

I also use a blower in the shop on a timer, this works really good. After I do step #2 and open the hood, I turn the blower on, and go to step #4. When the water temp is
good, I set the timer for 20 minutes and leave.

It's normal to hear water "moving" and metal "pinging" after shut down.

It's a 'Lisle' funnel guys :)

The single biggest change that made all of my coolant boiling go away (even after some hard summer sessions on the road race course)...... Evans NPG+. One of the best things I've ever done for my FD, and I've owned the damn thing since 1998 :lol:

I guess the OP can check their pressure cap for the radiator to make sure it is holding the proper pressure to prevent the boiling of the coolant.

I will most likely convert to npg+ this winter as well.

John

i do this when i park in my garage, i just park it and pop the hood with a fan in front of it to cool it and get the smell of exhaust out. Come back about 5 mins later and start it up to get the rest of the coolant circulating, temps drop and turn it off.

what are your temps rich? street and track?

Early on with both my FDs, I had similar symptoms, and replacing the clamps to all the coolant hoses appeared to improve the situation. I then took further measures. However, I learned that cooling the engine comes with some important CONs to consider carefully:

Koyo = no more free sauna for myself and female passenger and no longer being able to fry eggs on the center console.

Vented hood = 4 years of people asking "What about when it rains?"

re:^ To each his or her own, but I wouldn't like to drive a car that requires me to pop the hood and stand there every time I stop. :)

Do some research on Evans, hombre. There are some very nice threads floating around this forum. A little old but still very relevant.

Evans has a much higher boiling point (like 370F vs 264F for 50/50 IIRC), allows you to run a zero pressure cap, and is a claimed lifetime coolant. I plan to update my build thread with lots of good info and my experiences, so stay tuned :)

this i knew, i was thinking of doing evans a couple years back, but just was too lazy to do the conversion of making sure all coolant was flushed out because i read that evans cannot be mixed. i cannot complain about my temps tho. maybe if i tracked the car i would switch to it.