Hello all i have a 88' N/A with a fresh rebuild, after I drive the car for a bit the "add coolant" idiot light and buzzer come on. I immediately pull over and the coolant cap is released and has blown coolant all over the engine bay.

My temperature gauge does not go above half when this happens, I have also had these conditions happen at idle. I also do not have a fan shroud as the car did not come with one from the previous owner.

What should I do?

I have not tried to bleed the air out of the system, nor have I replaced the thermostat or coolant / radiator caps with OEM products. I figured I would start there, but any other advice would be appreciated. Thank you

 

well first off you need tht fan shroud.

 

Bleed system, replace cap, add a fan shroud, look for ANY coolant leaks, then report back.

 

new thermostat and bleed out the air, what do you mean it blows coolant all over engine bay?
do you not have the hose going to the reservoir tank?

 

I do have hoses going to the reservoir tank. It looks like coolant comes out of the filler cap and blows to the back of the engine bay as well as all over the intake, secondary fuel rail, pretty much anything on the passenger side is covered in coolant.

I don't get the car back for a day or so as it is getting tires put on it, (2 were down to cords from previous owner.)

So in the meantime I will try to track down a fan shroud in MT...

 

Coolant should never leak out of the filler cap and spray all over the engine bay. You need to replace the cap, as it's clear it's not making a seal anymore. It makes sense that the cap doesn't leak while the coolant is cold/warm, but once pressure builds the valve will open to the overflow tank. Once this happens you'll have coolant flowing around the poor seal, which means instant leak.

 

I have recently replaced the filler cap with a new one, (Non OEM) and still had the same problem.

Do you think maybe the seal on the thermostat housing could be bad?



Thanks again.

 

What PSI is your cap rated at?

 

13 psi

 

Also another question my car does not have this sensor.



Could missing that sensor also be part of my problem? Or does that sensor just affect initial startup?

 

get some sealant and take the cap assembly off and reseal it.. clean it up. I dont have a gasket there, just good application of sealant will do.

 

There is an oring underneath the piece your arrow points to. You can buy a new one for $4 from Mazdatrix: http://www.mazdatrix.com/getprice.as...m=15-1740-N326. http://www.mazdatrix.com/b8.htm

That is a thermoswitch for the electric fan on automatic and turbo models. Manual NAs never had it. The thermostat cover will just have a hole blocked off in that location.

 

While I was trying to get all the air out of my coolant system after about 5 minutes it looks like my coolant starts to boil. Steam was also coming off the radiator cap.

Attached is a video of what I witnessed.

<embed width="440" height="420" type="application/x-shockwave-flash" src="http://v5.tinypic.com/player.swf?file=156ya2o&s=5"><br><font size="1"><a href="http://tinypic.com/player.php?v=156ya2o&s=5">Original Video</a> - More videos at <a href="http://tinypic.com">TinyPic</a></font>

Sorry for the horrible video quality.

What should I do now?

 

poss. broken housing,around compression area..coolant seal blown out and compressions going into cooling system??

 

I sure hope that is not the case as this is fresh rebuild with probably 2 hours on the engine...(crossing fingers)

 

you need the cap assembly with the nipple that goes to the overfill tank. but you got the overflow hose on the rad so i dont know how that would work..

or do what i did *s4 assembly w/s5 rad* since you got a cap and the overflow hose on your rad, should work.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/need-help-my-cooling-configuration-882748/

 

So you are saying the hose from my radiator needs to go to the over fill container?

In the video i posted the hose coming off the radiator cap goes to the overfill container, just doesn't show it in the video.

I have all the hoses hooked up like the FSM shows on page 3-2 of the cooling section.

Any other suggestions?

 

well where does the hose on teh rad go to? im not familiar with s4 rads

 

The hose on the radiator in the video goes to the overflow tank.

 

Early S4s had the radiator cap and hose to the overflow tank on the radiator. Later S4s moved it to the thermostat cover. Yours looks to be setup normally; albeit annoying to have 2 radiator caps to deal with.

The video showing coolant boiling doesn't mean much of anything. With the cap off, the system is not under pressure, which means the boiling point of the water/ethylene glycol solution is much lower than under normal operating conditions. Liquids under pressure will absorb more heat before they boil.

Replace the o-ring on the thermostat cover, and see how it goes from there.

 

i had a problem with coolant leaking out here once

turns out the stupid plastic thing was cracked in the side. got a new shiny aluminum one

 

Turns out that once I switched my new non OEM cap that was on the thermostat housing with the one on my radiator my problem went away.

So now when I am driving my temperature guage stays in the lower quarter of the guage. This is also without a fan shroud, do you think it is worth it to add a fan shroud?

 

The fan shroud is there for a reason, you NEED it.

 

Get a shroud ASAP!

 

pu a hole in the cap