Hello All!

Well, I'm pretty sure that my coolant seals are gone, but just would like to have some confirmation from you guys. pictures are worth a thousand words, videos are worth a million:

If this link doesn't work:
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Use this (only works in area 51 for some reason):
https://www.rx7club.com/showthread.php?t=555736

In the video, the car was idling at 185F-190F, which is well below the boiling temperature of water+coolant. The little bubbles never stopped appearing, therefore leaving me to only 1 conclusion... bad coolant seals.

Any comments??

Thanks!

Howi

 

damn...im afraid for you...how many miles on the engine

 

is it the original motor? has it ever been overheated? is it blowing white smoke out the tailpipe? it is hard to start? is the coolant overflow overfilling?

I didn't watch the video.

 

It's not the orignal motor, currently it has about maybe 30 to 40k.
It's a mazda reman.
it doesn't blow white smoke.
it's not hard to start.
I ran a clear overflow line, and have been watching it for weeks. the engine spits out mixture of air and coolant, and also sucks it back in.

you know what, i've already done too much to diagnose my problem, so i made the ultimate tester to see what the heck is going on in my coolant system. I made the video so i don't have to explain and people don't have to read.

please don't assume that i'm a noob. watch the video.

howi

 

video doesnt load..ive let it sit for 5mins to load and i have 3mbs

 

ditto..

 

Did you pressure test the system Howi, thats the sure way to tell....

You can see the vid. now....Looks like a coolant seal to me, Lets start the rebuild

 

hmm.. sorry guys! my friends could load it no problem though. Try this one then:

http://youtube.com/watch?v=4p5wlc6Ec6o

that's the only thing I haven't done Jim. I'll be doing that some time this week!

Howi

 

THAT much air and it was burped at the TB? It's suspicious that you don't have any other symptoms. Pressure test will tell you for sure.

BTW Area51 link works if you click on the vid (not the play).

 

sorry for this question but
What ic duct is that on video?
Were I can buy one?

 

go get a block tester kit from napa and do a pressure test.
that is a serious rig you made although i'm not sold on it for diagnosing the problem

 

Doesnt it usually start bubbling alot more than that when its a bad coolant seal? I saw one being tested at Mazda one time and the put a put funnel...sorta like what you have on there and it came out and got all over the engine after it warmed up.

 

I was able to see the video - until you moved your camera to look straight down on the bottle, I couldn't see anything. But then I saw that's a LOT of bubbling. The call it the champagne bubble test since the bubbles are normall tiny.

While that's an impressive rig, I would take it to a rotary shop and let an experienced eye decide. If that's very inconvenient (sometimes the nearest rotary guru isn't close) I'd pay a local shop to do a 1) pressure test and 2) hydrocarbon detection test. If it fails both of those you can bank on shot seals.

Dave

 

my TB is bypassed. the water level in my rig sits way higher anyways, so it should have bleed the air out of the entire system.

sorry man, you have to ask jim kutschke about this. I have no idea.

me either. That's why i'm asking you guys for your opinion. I think that although my temp gauge reads 190F (which is below the boiling point of coolant+water), it could be much hotter in the engine, causing the coolant to boil. In other words, perhaps this is normal.

I have no idea....

ya that's a lot of bubbles indeed. for sure I'll do a pressure test in the next few days and see if I can find more info about this problem/phenomenon. what's hydrocarbon detection test anyways??

Thank you everyone for your help so far. I guess what I'm really wondering is, does the coolant in an FD normally boil under atmospheric pressure? I hope someone w/ some experience will be able to tell me.

Howi

 

There is one way to tell for sure if it's the water seals. Have it owed to a work shop that has a sniffer that can detect exhaust gasses. And u will tell at once if it is a broken water seal.

JT

 

I agree...also does your coolant catch tank overflow when you come to a stop. Also how high do your coolant temps climb when you shut the car off?

 

They have sensors that can tell if those bubbles are hydrocarbons (exhaust gases) or something else like air.

When I did this test on my own car, I saw almost no bubbling at all. I think the boiling point of coolant is much higher than 212F, but offhand I don't remember the number.

Besides, if it was actually boiling I think the bubbles would have looked a lot different - more like a boiling pot of water.

Dave

 

Thats what i saw then....boiling out of the Funnel like crazy. Guess thats a sure way of knowing its a bad seal.

 

Try cracking the throttle while you've got that coolant expansion tank installed. If the amount of bubbles change nearly immediately when you rev the engine, it's pretty safe to say that you've got exhaust gases in your cooling system.


I do agree that you're probably seeing some localized boiling, and I think it's due to the coolant lines running through the twin turbos. I'd like to build a coolant expansion tank that is pressurized using the factory radiator cap, but it's a low priority right now. My car has a quick-responding digital temp gauge installed, measuring the OEM temp sensor on my rear rotor. The rear iron's temp doesn't change too quickly based on heat input, it seems to be heat rejection that makes the difference in system temps. For instance, a second gear pull doesn't get the car nearly as hot as just stopping and idling with the fans turned off.


-s-

 

Here's a video of me flushing my coolant, trying to show people how much air can be removed from the system by using a coolant funnel like the one you've got. I forgot about the lower boiling point of non-pressurized water (213F, which is lower than turn-on temp of the cooling fans), and you can see that the water boils right before the end of the video. You can see which of the bubbles are from air pockets, and which are from boiling. At some points of the video, there's an IR temp gun pointed at the filler neck, to give an estimate of the coolant temp.

http://www.youtube.com/watch?v=kplCNrR2juw

-s-

 

if it is constantly bubbling from cold to warm then that rules out boiling, i would say almost positively that it is the beginning of a failed coolant seal/cracked iron.

 

Thanks everyone for your help. I borrowed a coolant pressure tester from a friend and tested on my car. FOR SURE my coolant seals are going because:

1) it bleeds of the pressure slowly, without leaving anything on the ground.

2) after I pressurize the system, I tried to start the car and a lot of white smoke came out. I also had a hard time starting the car.

3) I released the pressure back to 0, pulled the EGI fuse, and cranked the engine for about 10 seconds. By doing so I actually mangaed to pressurize the coolant system by 3 psi.

Also special thanks to scotty305 for uploading the video for me, that's exactly what I was looking for! Karack is right; mine would bubble from cold to hot, none stop.

From this experience, and the fact that we have 2 videos in this thread (a normal engine and an engine with a blown seal), I draw the conclusion that a coolant funnel has been proven a very cheap, easy, and effective way to see whether you have blown coolant seals.

Thanks again for everyone's help!

Howi

 

Well, sorry for the bad news. What are your plans for the motor?

 

Soon I'll be uploading another video, showing the same engine about one year and 15k miles later. I'm pretty sure my coolant seals are failing slowly, I've got a stream of tiny bubbles that appears when the car warms up and the thermostat opens. I'm going to do everything I can to maintain and upgrade the cooling system before I rebuild the motor, I'd like to see how long you can go on 'bad' coolant seals if you baby the car...


-s-

 

that tool is quite nice, i actually have one premade that you can buy from tool dealers like Matco or Mac tools for about $30.

sorry to hear the bad news about the engine but i expected this outcome.