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Discussion Starter · #1 · (Edited)
hey guys, need help with this one. just started 2 days ago although cooling system hasn't been the greatest for a long time. :mad:

Car has been fitted with a near new adrad radiator yesterday, no leaks, rad and piping all checked. New tectaloy 100 coolant in radiator.

aux fan kicks in but then cannot turn off as the coolant temp increases to 100 degrees + thermostat still seems to be running.

If i turn ac fan on and vent heat in the car, temp will lower minimally

No thick white smoke, no oil in coolant or coolant in oil + oil cap is clean etc. car is undrivable as temp will get to 3/4 of the stock gauge before I give up and pull over. :tdown:

At the moment i'm leaning towards water pump or headgasket. anything else ive missed? I have also uploaded a video on my friends youtube to show the coolant while the car is running

any help or advice very much appreciated


This is running the car at idle gauge needle in the middle, so around 80-90 degrees?
 

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When you say the thermostat seems to be running....how can you tell ?

Most of the time they get stuck half open, which is no good in this type of heat.
I would just replace it anyway, they cost about $20

A couple of ways you can tell if you have a head gasket problem

1.coolant lost
2. overflow reservoir seems to be above the fuller than normal, butt when you take off the cap (after the engine cools down) the radiator is not full to the top.
3.Radiator hoses balloon up before the engine warms up (in the extreme cases) and you take off the radiator cap and coolant pisses out everywhere (this is more the sign of a cracked or warped head.

I would start by changing the thermostat.
 

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Discussion Starter · #3 ·
thanks chief tool :)

great advice, very reassuring. but im still worried about the air bubbles in the coolant. Did i maybe not bleed the air out enough or can a broken thermostat cause this?
 

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Discussion Starter · #4 ·
ill go down your list this afternoon. buying a thermostat shortly :)
 

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Discussion Starter · #5 ·
just to add in the reservoir has not been losing any coolant and it does not bubble. the only bubbles are from the radiator cap.
 

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if your getting bubbles when the car is stone cold, then its could still be the headgasket...

however once the car begins to warm up, it could be steam building up....its hard to say from you vid.

I tend to put the cap on once the car begins to warm up, otherwise the coolant expands and starts to spill out.

if your not getting bubbles in the reservoir, and there is no coolant loss, I would say keep driving the car until you notice either of those two things happening.

The new radiator : is it a proper turbo one, or a single row NA one ?

If its just a single row, it may not have the heat removal capacity esp in 40+ day temps....

Another way you can tell a blown head gasket, is that the car seems a bit down on power, but thats alot easier to tell on gutless cars where any power loss is pretty obvious
 

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Discussion Starter · #7 · (Edited)
replaced thermostat and gasket, but thermostat housing had a small hairline crack that snapped when i was bolting it back on. Could this have contributed in any way? pressure loss etc? however i didn't notice any leaks beforehand.

Getting my hands on another housing tomorrow will update then. thanks for the help cheif tool.

The new radiator is a single core N/A one, swapped it over very cheaply as the previous radiator developed a leak shortly after the car began to overheat. I also had 2 small rubber coolant lines develop leaks that had to be replaced too.

I will check all your suggestions once I have the cooling system back together.
 

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The crack in the housing may have caused a small leak which may have gone un noticed for a while.....

I would maybe take the opportunity to replace all the rubber coolant lines, like the turbo coolant lines, the oil cooler lines, check the heater hoses etc.

I recently had to replace the turbo gasket on my GC, and when I pulled off the turbo, I discovered that the shop that put my Garrett on, had used fuel hose for the turbo coolant lines, fuel hose is not compatible with glycol coolant and had become so brittle that both ends of each hose snapped off, one end had cracked, and coolant had been leaking for some time.
I could never find the leak, but I could smell coolant burning on the exhaust pipe when the car was hot.....just as well I found it, it wasnt far away from bursting.

So it pays to replace this stuff long before it becomes an issue.
 

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Discussion Starter · #10 ·
true, thanks for the info

will grab the housing today and if this solves the problem, go over and replace rubber lines.
 

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Dodgy jobs! I'm currently working on an AT Turbo, and someone had done a repair on the coolant line that goes under the throttle body and I believe it goes to the oil cooler... can't remember. Anyway, they chopped the hose where it had burst... put a copper pipe, then attached fuel hose to it and attached it to the throttle body end.

Ok, so the genuine hose costs over 80 or 90 dollars... just buy a metre of heater hose to suit (probably $10 at Repco, if that), you'll probably use less than 40cm, and replace it! The old coolant line was swelling and ready to also explode... turns out that the turbo water hose blew and caused it to blow a headgasket... so I'm replacing all the hoses while I got it all apart.
 

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I dunnow every one has an opinion on thermostats,, I figure in Australia (at least in wa) you are probably better removing it altogether…
But if you have bubblesif it dosn stop after a day id be looking at a leek down test. Basically a snifter that can tell if the bubbles are co2..
 

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Discussion Starter · #14 ·
lol... gotta be the hot week we have had :(

well about a week before all this happened i had 2 rubber lines split small leaks on me.

one was under the throttle body and the other the turbo coolant line :( a small leak for a few mins wouldnt have cause alot of damage would it?

i stopped and barely drove on them before replacing them .

new housing in for $9 from "jollys you pull it" ( pick a part wreckers) in dandenong today

can anyone also tell me when the temp gauge is dead center, what should the coolant temp be? 82?

I also have a manifold leak again. Could this cause a car to run hotter?

another vid below, thanks alot for the help guys. took this after about 5 mins running.
no major bubbles in res or rad on startup etc.


so at idle it seems to be under control. got another problem now though, the cooling/aux fan is running non stop regardless of temp. what would cause this?

Haven't driven the car yet but will shortly. If this doesnt solve itself, the next step is what mr Mx6 just said, pressure test and sniffer test etc
 

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f*ck yeah just rip the bastard thermostat out.

theyre no good for nothing, at least not in aus.

why have 7 litres of coolant and 2" hoses, then restrict it down to like a 20mm at best orofice?

the one prob ive found with this, is the motor runs way too cold at night, and takes forever to warm up even on hot days.

i run 4.5 litres of coolant instead of the full charge, and no stat.

warms up same speed as stock, and it has never overheated, even on the hottest days.

ive had more cooling system issues than anyone with both my mx's

this is the only way ive found to make the cars cooling reliable.

just my 2cents
 

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No I would have to disagree, removing the thermostat is a bad idea.....

mine got stuck open during winter, and the drive to work on a winter's morning the car never warmed up....and thats in Sydney, Melbourne is a bit colder.

sure you can take it out in summer....but it is there for a reason.

Trust me, if you have a new thermostat, and its overheating...thats not the cause.

88 degrees is about half way, 82 degrees is about 25%
 

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Discussion Starter · #18 ·
cool so that could be the next option if my head gasket is ok. thanks for the input marty.

Iv'e heard alot of 50/50 yes and no on this topic of running with without a thermostat lol
 

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Discussion Starter · #19 ·
so keep the thermostat in :)?

cool so that makes sense. it was about 75 degrees at the top of the rad, so the stock gauge is getting around 80 - 88 at the thermostat housing.

I guess the only way to tell if the problem has been solved is to drive the car which im gonna do shortly :)
 

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Discussion Starter · #20 ·
im guessing the reason that the aux fan is running non stop now is due to the change in thermostat housing which has 2 sensors where as my old housing only had one.

whats the difference there?
 
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