Ok, so I actually have a laundry list of problems, but this is the biggest one and therefore the one currently being conquered.

A few weeks back, the temp would rise above normal on my drive home from work. The drive into work would be fine. So I checked the coolant reservoir and it was a little low, so I filled it up and things 'sorta' settled out. The only other problem at that time was once I got home and garaged it, the garage would be full of a smoke haze after the car had been sitting for awhile. I noticed some smoke coming from the big (only?) cat and figured, "alright, looks like its time to take it off or replace it". The temperature rising problem an intermittent problem.

Well, two weeks back, (with this lovely warm weather we've been having), it went from above normal to way above normal. I checked the coolant again, and there was plenty in the reservoir and in the radiator. I started noticing a noticeable amount of coolant under the car after it had been sitting for awhile. I visibly checked and could not find any coolant leaks. I did start noticing a smell of burnt coolant when I would have the car in the garage at night.

Well later that week I had an issue on the drive into work where the oil pressure dropped off and I had the car towed home and it sat for two weeks while I drove the wife's car. Long story short on that, the cable/contacts were dirty on the oil pressure sending unit, and after I cleaned and reconnected it, everything looked peachy with regards to the oil pressure. While starting it up and testing the oil pressure gauge out, I started to notice smoke rising from the engine compartment from the exhaust manifold area. I quickly killed the engine and inspected. The smell of burnt coolant was back and I noticed coolant pooling around the edges of the oil pan and dripping onto the drop 'cloth' under the car into what was a sizable puddle of coolant.

I have not noticed any active coolant leaks, but have no idea as to where the coolant is coming from. I'm also concerned about why engine is not cooling during use. I will say that the heat doesn't keep actively climbing, it just rises to above normal temperature, 60-80% up the gauge. I have a sneaking suspicion that the two problems are interconnected.

Sorry for the long post, but does anyone have any ideas as to where to start to find the source of the problem(s)?

 

Good possibility that the coolant o'rings behind the intake manifold are bad. Also recommend as preventive maintenance to replace your T-stat and radiator cap if they have not been changed.

 

in addition to what rx7doctor said, you might want to pull the exhaust manifold and turn the engine by hand to see if maybe one (or more) of the coolant seals are bad.

 

Thanks for the help Dr. I pulled the intake off Sunday and the O-rings were in pieces as I pulled the manifold off.

Replaced the gasket and the O rings and things are looking up. I stupidly forgot the T-stat before putting all the fluid in and testing it, so that's a job for tomorrow night. An initial test drive started to see some temperature hike, but as I turned around to bring her back home, the temp settled back out around normal. This makes me think that the T-stat is probably on its way out the door. (Please correct me if I'm wrong).

Diabolical: Thanks for the suggestion, I did not pull of the exhaust manifold for that check. I already know that the engine is need of a rebuild, I'm just delaying the inevitable. (Kinda happens when you're the second owner and the car already had 150K+). I figured if the o-ring did not fix the problem, then I know where I'd stand anyways, and there's no need to dump the $ on the gasket.

 

The t-stat is just old and probably not opening all the way. See how it operates with the new t-stat. There are other factors to consider also. 1 being the condition of the radiator. Meaning is there any type of blockage in the runners and if so, how much? The condition of the Fan clutch is another factor for temps at idle and low speed driving.

 

Replace the t-stat and rad-cap with OEMs from mazdatrix. They're only slightly more than bubblepack trash from the autostore. Consider getting a $130 radiator, possibly from radiators.com. I've replaced all 4 radiators in my 4 rotaries in the past 4 years as they approached or exeeded 100k miles.

If you replace the radiator, consider replacing the water pump with a $50 pump from rockauto.com.

Replace, without question, the radiator hose that runs under the beehive! Sure it costs $42 from mazdatrix, but you'll save time, trouble and money later on. Better than replacing it, when it rots out from oil drips, as it inevitably must, with off-the-shelf autostore 5/8 radiator hose: I've done that, but I didn't enjoy it.

If you're losing coolant every few days and your car starts with a cloud of white vapor from the tailpipe, try the temporary fix with colloidaly suspended copper which has been written up and reported on many times. It works! And can hold for a year or two for sure if done right.

Cooling system care is of primary importance to your rotary engine. Just Do It!

 

Get a good TStat and install it properly with the jiggle stick up.

 

Finally got the new thermostat in and installed, after burning off the spilled coolant, the car now starts up like a champ and has been running for a week with no overheating problems.

BTW, all of my hoses (and radiator) were in good condition since they were replaced a few years back by the previous owner.

Now onto the other problems.

 

^Think of them as "Opportunities", not problems. LOL.