In trying to diagnose our coolant over pressurization/overflow problem, we have performed a champagne test as was recommended a few days ago from many of the helpful members of this forum.

At this point this is what we have experienced.

1) A good number of bubbles. Do these look like seal failure bubbles or just air in the system bubbles?

Video of Champ Test

2) No noticeable white smoke from the back of the car, or coolant smells upon startup.

3) 3 starts (out of 15 total starts since I made it back from NY) have taken about 15 seconds for the car to turn over. [Fritz Flynn said this could be wet plugs from a bad seal].

If these bubbles are conclusive in showing a bad seal, we will forgo the Hydrocarbons test that searches for HC's, CO's, CO2's, O2's, or NoX.

Thank you in advance for any comments on these bubbles.

-Rotary4tw

P.s. Here are a few pictures... it pains me that something so beautiful has something so wrong with her...

 

Pretty inconclusive from what I can see in the video. You need to get a large yellow coolant funnel that attaches to your fill neck and run the car until your T-stat opens up. Then if you get a steady stream of FIRM bubbles that linger before popping, you MAY have a problem. If I were you, I'd do the blue liquid exhaust gas test as well to check for exhaust gas. Pulling the engine should be your last resort.

 

Pressure test the cooling system. The "bubbles test" isn't always 100%.

 

I dunno about a bad seal. Those bubbles were veyr small and intermitant(sp). On my old neon (i know its a piston engine, but it is a similar situation) with a bad headgasket, with the cap off like that the bubbles would come like crazy.

 

My coolant looked like it was boiling with 1/4" bubbles when I did that test so I think your video is inconclusive. (Watching that video gave me some bad flashbacks by the way ) Did you let the car get operating temp before you shot that video? Do an overnight pressure test and see if it holds.

 

After you drive around for a while, do you get a puddle of coolant under the passenger side front fender area? If you do, that with what I have seen in the video, I can can say with more than 90% certainty, you have a coolant seal problem. Run the HC sniffer test to verify. You can bandage the problem with block weld for a few weeks to a few months, but a rebuild is in you r near future, sorry.

 

hard starts

really hard starts in which you could run on one rotor until the other dries and fires

when your blowing steam out of the exhaust your pretty much done.

right know you may be able to drive the car for a while with no problems. I actually took one to two different track events before it finally died.

Don't sweat it just save for a new engine. Don't rebuild it because the housing are most likey warped and it will be costly.

 

also don't use block weld because it won't last long and it will gunk up the rad etc...

 

From your photos, the car appears to be missing the undertray that forces air through the radiator. Without it, air will bypass the radiator and flow under it instead of through it. This is definitely one of the things that is causing your car to overheat, although from reading your previous thread, I'd wager that you've got some coolant seal problems as well.

I'd recommend you do the following things:

1. Order a new undertray. It's a Mazda part, from Japan-only models, so you might not be able to get it from your local dealer. I think Ray at Malloy Mazda can get them, but I'm not sure. More info here: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/99-bumper-under-pan-410165/

2. Pressure-test the cooling system. Some auto parts stores will rent the tool to you for free (Autozone).

3. Pressure-test the cap while you're at it.

4. Get a coolant burping funnel, like this one: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/radiator-cap-funnel-eliminate-air-bubbles-342309/

4. Replace the coolant, with a 50/50 mix of water/coolant. This will raise your boiling point and give you a little more of a safety margin. Use the coolant funnel to burp the system so you won't have air bubbles. Do this again about a week later, just to be safe.

5. Get a water temperature gauge, and do some research as to which temperatures are safe. I think 230 F is considered too hot by many owners.


6. Install a Thermoswitch from an FC (86-91) RX-7, it will cause your fans to activate at lower temperatures. Or perform the "fan mod." Search the FAQ for this info.


Good luck,
-s-

 

how exactly do you perform this champagne test

 

We've went over this a couple of times....

 

[QUOTE= You can bandage the problem with block weld for a few weeks to a few months, but a rebuild is in you r near future, sorry.[/QUOTE]
Have to laugh at this. I didn't think it would work (and it seemed like forever) to get all that damn soap outta the cooling system.....but it lasted me for a year and I was boosting 10 psi on a regular basis and 100 to 140 MPH runs weren't uncommon. It might have gone longer if I had kept my foot out of it a little less. Jack

 

We had some more hard starts tonight after Church Softball... and we saw our first cloud of white smoke upon startup.

Also, I'm only boosting 4psi at WOT, so there are some other things that are out of whack. I'm not going to worry about boost, or any type of WOT untill I get this engine issue resolved. From what I have read the 2nd turbo isn't even activating... More issues for another time. If we have to put in a new engine, hopefully we can get everything else functioning too.

Thank you for the comments, especially about the undertray. I'll look into it asap.

-Rotary4tw