Help!! Engine Overheating!!
 

Here is the situation:

After my recent rebuilt and after solving some issues with computer resetting and hasitation thing on the RPM by changing spark plugs and spark plugs wires. I started to go full throtule with the car and i found out that the car from 1K RPM to 4.5K RPM is ok and turbo is spooling, but after that the power is not dicreasing or increasing and you can hear the 2nd turbo screaming but with no power!!

After that i realized that the car is heating when i puch it beyound 4,5K RPM , so i stoped doing that, but i dont know whats happening now, the car started to eat water!! everyday when i check water in the morning its lower and i have to add some + just yesterday after a long trip i stopped the car and the temp was normal, but after 20min i started the engine again and the gauge was above the middle and it went back to normal after a few seconds and again raised up to Heat after a few seconds also!!! So i stopped the car and i left it for an hour, went back again and i added a lot of water as some have went out of that white water tank on the lift side. Now i drove it for about 15 minutes, temp gauge was normal, but after that i turned it off and opened my hood hearing water bubbling in the engine and some water presure noise near the AST!!!

Sorry for talking for long, but what do you think???

If you've had a recent rebuild done, I would first check to make sure the cooling system has been burped to get all the air out. Burp it again, search for the how-to. Disconnecting the throttle body hose while filling at the filler neck is a popular way.

The car eating coolant and sending some out the overflow bottle can be an indicator of a coolant seal on the way out. though I doubt that's the case on a new rebuild. Still, it can't hurt to double check. Is your white smoke on startup excessive? Pressure test the cooling system, as well as testing your seals this will also help you identify any other leaks. Also you could check using the champagne trick - look for small bubbles in the coolant at the filler neck with the engine running.

After ruling out the blown coolant seals (lets face it, not likely on a new rebuild) you might want to check your thermostat, pull it out and put it in some boiling water with a thermometer and make sure it opens at the specified temperature. Also check the condition of your radiator.

Don't need to check things in that order, that's just the order I would check in. In Saudi you might want to consider an aftermarket (bigger) radiator if you haven't already, as I imagine it gets quite hot. Then again, we get relatively hot in Perth and I've not had any overheat issues. Don't go over 210F even in 100F+weather.

Oh and one last thing - if you don't have an aftermarket temp gauge, buy one and put it in. The stock is weighted too heavily to the middle, and won't tell you you're overheating untill too late......

Hope that helps :)

Thanks man for the assistance....

There is smoke on startup but not an excessive ones, but there is some some small bubles only when i fel the filer nick!!!!

well that mean any thing?? and beside i dont have a thrmostat at all i have removed it!!

Running without a thermostat is a bad idea.

Also, for filling the coolant, fill here:

http://mahjik.homestead.com/files/FD...iller_neck.jpg

But what do you think of the symptoms i gave ? is it a bad sign or something :(?

Beside the cap for the area you should me above its a flat cap from below right?

I think that the first thing you need to do is get an OEM thermostat. Then go from there.

I'm sorry, I'm understanding what you are asking.

I think he was asking if the cap you showed was a plain (fill cap) or a spring-loaded pressure-relief (AST-type) cap. If I understood correctly, the cap in question (fill cap) is a plain (flat as viewed from the bottom) cap.

YES , your right i was meaning what dave mentioned. I was just making sure that the filler cap is a flat one from inside? or should it be with a spring like the one on the AST?

The filler neck should be a non-spring cap and the AST should be a spring cap.

i will try to purchase the aftermarkwt thermostat one ASAP.

you are better off getting the thermostat from the dealer. at least you will know it is the correct one.

As Alberto said, the aftermarket ones sometimes cause problems (slightly different designs, etc.). The Mazda one is the safest one to get.

Then sure i will order the stock one

Bubbling in the coolant doesn't necessarily mean you have blown coolant seals, it can also indicate some air trapped in the system if it wasn't bled properly. So don't get too worked up over a few bubbles just yet.

I once had a mechanic tell me my rotary engine had a blown head gasket(!!??) because there were some bubbles in the coolant. Turned out the system wasn't bled properly, and my seals are fine.

I'm with the others, you definately should get that thermostat back in there.

I'm with the other, get a t-stat. Also, it wouldn't hurt to make sure your fans are working properly.

Can't you burp the coolant by opening the filler neck, adding coolant, revving some and letting it idle? The bubbles will eventually work their way to the top, and the level will drop. Then add coolant again till it's topped off, rev, idle, wait... repeat etc. That's what I do, and it's always worked...

Oh and Jed, if you need parts from the dealership, let me know. I can get it from Malloy Mazda (cheapest place) and ship it over to ya. Also, like I said earlier, you need to install that boost gauge to see what on earth is going on w/ that 2nd turbo. A boost pattern will help these guys diagnose your problem.

~Ramy

Can anybody explain to me why it is that we need the thermostat? Isn't the only purpose of the thermostat to restrict the coolant from circulating until the engine has warmed it to a given temp? Once you reach the temp, it's always open isn't it? Doesn't that mean that it's only good for 5 minutes out of the day and a liability for the rest of the drive (in the situation where it by some freak chance isn't opening)?

I only ask because I've removed it without any hiccups. But I don't know whether this is due to the fact that I live in CA and the weather doesn't get cold. I warm up to 60 celsius in about 4 minutes and the car drives at 80-90 until cool down. I shut down at 65-70 and this takes about 3 minutes with fans on. Coolant level is perfect. Also, I have an APEXi temp sensor tapped into the coolant housing.

Anyway, let me know your input just in case I've done a bad thing without being able to see the symptoms. I still have the OEM thermostat so it would be 30 minutes to put it back in.

-Huy

Huy,

Just so we don't get off-topic, please consult the following threads, which have discussed removing the t-stat and it's pros and cons:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/gutting-thermostat-146501/

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/car-very-hot-removal-themostat-229455/

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/removing-thermostat-112751/

Thanks
~Ramy

will i guess its better to start by adding the stat and see how it goes first...

did you do a vacumm hose job any any chance? your boost issue might be caused by missing pills in 2 vacumm lines, the wastegate control and turbo pre control actuators.

Actually, the guy who rebuilt the engine, have done also the vacums job!! but as far as the current condition and that non working second turbo, im sure that it needs to be re checked again...