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Background: S5 n/t coupe with MT, original owner, Mazda reman engine installed in Aug 2002, current mileage 163,870 on reman. Bought the Mazda reman from Ray Crowe when he was still PM at Malloy Mazda in Woodbridge, VA.
Problem: Car has been out of service since Tuesday, Sep 27th due to coolant leaking into oil.
Car has been slowly losing coolant for the past 2+ years. Have had to add usually a pint to a quart of coolant about every couple days to every couple weeks. Coolant consumption was variable. Began in 2017 sending used oil samples after every oil change to Blackstone Labs for chemical analysis. Latest report is attached. Results looked good for 2017-18, than starting in 2020 Blackstone started noticing high sodium concentrations in my oil samples. Sodium indicated coolant leak into oil. The sodium concentrations have increased from 2020 through my last oil change on 2022.
During Sep 23-26, I drove my RX7 down to Charlotte, NC to attend the Carolina Nationals drag races. Drove 965 total miles getting 25.2 MPG averaged over three straight interstate runs. Needless to say, the car was running great. Also, had no problems over the past several years and without a smokey exhaust.
Tuesday morning, Sep 27th, I had doctor's appointment several miles away from the house. I didn't check the coolant level that morning as I usually have done. On drive back home, a few miles from the house, the low coolant buzzer goes off. Scared the $hit out of me. I don't know why Mazda made that buzzer so loud and obnoxious! I was driving on the GWMP parkway at the time, which has no shoulder so I couldn't easily pullover. Drive about a minute, then the buzzer shuts off. What a relief! About another minute and it comes back on. So, now about 1-2 miles from the house, I notice the temp gauge is now creeping up to about 2/3 way, but still in the safe zone. It's normally 1/2 way into the safe zone. So, I'm about a half block or so from the house. I cut the ignition, put car in neutral and coast the rest of the way home. After about an hour and once the car has cooled down, I pop the hood and tried adding coolant. I filled using about the last 1/3 bottle of premixed coolant and it still wanted more. Then, I started filling it with distilled water. It took a half bottle and still wanted more. In the meantime, I had the engine running and without any issues except the leak. It was running as it normally did without any smoke coming out the exhaust. Something was wrong here as I wasn't able to top-off the coolant. I then pull out the dip stick and a chocolate milk colored mix of oil/coolant starts pouring out. I then mumbled those famous words "oh ****" and shutoff the car. Its been sitting since.
After doing some searching on the web, it appears to me that the most probable cause of this would be a leaking front freeze plug. A few other people had similar problem and the cause was due to a rusted or mis-seated front freeze plug. Apparently, there are two different sized freeze plugs (20mm & 30mm) in the S5 front iron. If one (or two) plugs start leaking, than that's the only way that coolant can possibly leak into the oil pan.
So, I already contacted Ray Crowe (he's now PM at Malloy Ford in Falls Church, VA) and ordered all the parts (and more) that I need for this job. He's does business through NuCar Mazda in New Castle, DE. Ordered 25+ parts (mainly gaskets, seals and o-rings) and had them delivered to my door in a matter of days! Ordered some other parts from Goodson Tools & Supplies. Hopefully, this will solve my problem. I'd like to keep this rotary alive as long as possible.
Been pretty busy with other stuff so haven't had a chance to start working on it yet. Looking like it's going to be a big mess to clean-out this oil/coolant mix. Hopefully, I'll be able to get started on this job pretty soon. Not looking forward to it. Any comments/suggests or words of encouragement about this job?
My first time ever pulling an engine took just about 4 hours. I had the front end of the car on stands with the passenger wheel removed. I left the hood ON, but propped it up a bit further. I'd recommend getting a engine hoist level. I only had a strap and it makes getting it seperate from the transmission (and reconnected to the transmission ) a real pain in the butt. A level bar on the engine hoist will save time and cussing. This 4 hours included pulling the engine and main wire harness together so there was some passenger side under dash work. I've never done it but it really was not all that difficult. Move things and remove them from the engine bay to make room. Radiator, fan shroud, battery, airbox, ect..ect.. Give yourself room and label bags for small parts and where they go.. Once your engine is out face the front cover towards the sky with the flywheel on a hard flat surface. from there you can remove the front main bolt and front cover ect.. to access your freeze plugs if that is in fact what is leaking. Always replace gaskets with new. Always tape your intake and exhaust ports off once your manifolds are removed to prevent dropping debris into the engine
My first time ever pulling an engine took just about 4 hours. I had the front end of the car on stands with the passenger wheel removed. I left the hood ON, but propped it up a bit further. I'd recommend getting a engine hoist level. I only had a strap and it makes getting it seperate from the transmission (and reconnected to the transmission ) a real pain in the butt. A level bar on the engine hoist will save time and cussing. This 4 hours included pulling the engine and main wire harness together so there was some passenger side under dash work. I've never done it but it really was not all that difficult. Move things and remove them from the engine bay to make room. Radiator, fan shroud, battery, airbox, ect..ect.. Give yourself room and label bags for small parts and where they go.. Once your engine is out face the front cover towards the sky with the flywheel on a hard flat surface. from there you can remove the front main bolt and front cover ect.. to access your freeze plugs if that is in fact what is leaking. Always replace gaskets with new. Always tape your intake and exhaust ports off once your manifolds are removed to prevent dropping debris into the engine
Good luck and have fun!
Thanks for the tips and words of encouragement. Looks like you've got a pretty decent work area there.
I have all new parts including gaskets, oil seals, o-rings, etc. I recently bought over $300 worth of parts from Ray Crowe. That's in addition to the radiator, heater, misc. coolant hoses, belts, etc. that I bought a few years back, but have yet to install. I've got more parts and extras than I'll probably need.
I'm retired Army civilian so I have base privileges. I'm planning at doing this job at the Quantico MCB auto hobby shop. I can rent a lift or flat bay, and I have access to all shop tools such as impact wrenches, hoists ant transmission jacks, parts cleaning stations, hydraulic presses, etc., should I need them. In other words, I have complete access to a full self service auto shop. There are also trained auto techs available to ensure all work is being done safely and to assist those who need help or have questions.
Right now, I planning on getting started on this job within the next week or two after the Thanksgiving holiday.
i'm not sure if its easier to pull the engine or not, it probably depends on what other work you're planning on doing.
my first thought is to pull the oil pan, and just bolt the engine mount back (loosely to hold the engine), and then you can pull the water pump and front cover. that kind of assumes that you're only fixing the one problem though
i'm not sure if its easier to pull the engine or not, it probably depends on what other work you're planning on doing.
my first thought is to pull the oil pan, and just bolt the engine mount back (loosely to hold the engine), and then you can pull the water pump and front cover. that kind of assumes that you're only fixing the one problem though
That's exactly my plan of attack! We'll see where this leads.
Do you need to pull the oil pan or just the bolts that go into the front cover?
Both. The oil pan bolts partially to the front cover. You can't remove the front cover unless you drop the oil pan. The oil/coolant mix also created a big mess so everything needs to be removed to be cleaned.
11-15-22, 02:10 PM
