Okay I'm having quite a weird issue. After warm up I'm getting very light steam from my top radiator hose. The area where that hose couples to the radiator next to the headlight. Right when power fc hits 82c it happens. There is no leaks and it's not even wet In the area. Temp never went above 82c but to my understanding with the pressure the water boiling point is 103c. Is my power fc not reading past 82 for some reason?

I opened the system for a new thermostat from mazda as well as a new water pump and a ast delete. Brand new top from a FC from mazda and pressure cap from mazda. I should also add that their is some steam coming from the cap as well. Car never been overheated and everything was fine prior to those.

 

What is a 'brand new top from a FC from Mazda'?

Did you not have any of these issues until you did the work hinted at, i.e. AST delete, new water pump, new cap? If you were trouble free until then, I'd go back and look everything over real good to see if you missed something.

 

In the attached picture, can you tell us where you are seeing the steam? Which color area or areas? Blue, red, or pink circles? Or somewhere else?

 

The brand new top is the top used in the AST delete. The one with the nipple for the overflow tank. It also came with a pressure cap. Car was trouble free before I brought it down for 2 months for a bunch of mods. probably going to find a way to fit my AST back in and see if the cap one goes away.

Very light steam at the pink and at blue its as thick as if your boiling something in the kitchen, same color and thickness. I will say that it doesnt smell like coolant either. Running 70% water and 30% coolant.

 

You probably have a small leak when the cooling system gets pressured when the car is running. It could be due to worn rubber hose and / or hose clamps. Highly recommend replacing both with OEM components. Ray Crowe at Malloy Mazda can get the correct parts for you cheap.

Hoses and clamps often get damaged when removed to do other mods. Especially as the parts get older and experience more heat cycles.

 

Sometimes it is hard to get a good seal once it is broken but it doesn't sound like the o.p. necessarily fiddled with any of the hoses now leaking.

Odd.

 

Those hoses were removed completely while I was doing the work. They have 30k miles on them. I probably do have a leak from the worm gear clamp digging into the hose. Didn't know a leak can be steam instead of actual liquid. I probably have a defective pressure cap if it's steaming too?

 

^ More than likely.

 

Coolant leaking on a hot surface (like exhaust component) will cause steam. This is likely what is happening. Fix the leak.

 

Yeah I'm just going to order a new upper hose from ray and stock clamps and see if that fixes It.

 

How did you route the AST delete? I don't see the nipple on the filler body under the cap. You need to get the filler body off a 2nd gen from Mazda and run the overflow hose to that nipple. You also need to run a sprung cap now as you will be losing the one on the ast. Personally I feel an AST is just another component to fail and clutter the engine bay. We haven't ran one in 16 years and have never lost a coolant seal. You probably have a very minor coolant leak. Replace the hose and put on some good clamps. Also, if you have oxidation buildup on the radiator hose nipples make sure to clean them off first or you may not get a good seal.

 

He wasn't the one to post the engine bay pic. OP did state that he did purchase a new FC top so I'm assuming the parts right but good point on the hose routing.

 

Yeah i have fc top with stock fc pressure cap. I think it's leaking because there was steam from there too. Unless that top hose isn't sealing the best which is directly under the cap and may look like my cap Is leaking. But it Is brand new.

 

Theres a o ring underneath it. Is that bad?

 

New o - ring came with the top.

 

I've had defective hoses leak between the fibers of the multi layers actually.

 

Whoa that's interesting.

Anyways on the subject of hoses I heard the overflow hose has a restrictor

 

Whoa that's interesting.

Anyways on the subject of hoses there's a plastic piece midway in the overflow hose. Is that a restrictor or something? Can't be a check valve since coolant has to flow both ways in that hose. Just wondering if I can cut past it to shorten the hose going to the filler neck.

 

Still does it. A lot less now though. Brand new hose and clamps from Mazda. Maybe a pinhole in my radiator or something?