wanklenoob

Hello all, I'm new to this forum, and I am also new to owning an RX-7. my username speeks for itself considering I spelled Wankel wrong. Any way here is my problem/story: I have owned several mazdas in the past including a 626 a 929, and a protege. I always dreamed of owning an RX-7 and find Rotary engines very interesting, but alas, I never could afford one =( but less then a week ago I spotted an 85 generation 1 RX-7 in a creme color, and I was drawn as if a moth to a fire. the price was fantastic, and I test drove it twice and the engine seemed to run great despite the age. the oil was just changed and it only had 130,000 miles on it. The body had a few dents but nothing noticible unless looked for. The interior was spotless and it seemed like a dream come true! I knew in the back of my mind that if I were to purchase it, it would most likely fail and I'd spend time and money repairing it...well I've had it less than a week and my speculation was correct, much to my dismay =( I drove it for a couple days with little trouble, but as of yesterday when started (I give proper warm up time and choke etc.) the RPM's would run very low and sometimes it would stall. With some fiddling I could avoid this but then it got worse; in stop and go traffic my ADD COOLANT light and buzzer went off. I stopped the car immediatly in a parking lot and checked the radiator and added water. I checked it again after about an hour and added more water. there wasn't really a lack of coolant that I could see. I checked the hoses for leaks and couldn't see any, but this doesn't mean there isn't any. There was a coolant puddle but it seemed to be bubbling up under the cap. I waited about 6 hours and tried to start it again. it starts fine but the ADD COOLANT light again comes on. I researched my problems and found that stop and go overheating is caused mostly by a worn out fan clutch, but the fact that I tried to start it 6 hours later and still got the light leads me to believe it is something else. I refused to drive it home without knowledge of what the problem was so I had it towed by AAA. I'm going to try and flush the system and replace the hoses see if that helps. But I'm worried that it might not....I fell in love with the car at first sight, please don't let it be a short relationship I need some advice!!! THANKS!

trochoid

iTrader: (6)

Welcome to the forum and the Darkside. In my sig line are links to the online FSMs, carb manual and other rotary related reading. DL whatever you need and start reading/studying.

First, remove the radiator cap, start the engine and look for 'champagne' bubbles in the coolant. If none found, good, if you have 'Don Ho' coolant, it's rebuild time. No bubbles, check the heater hose under the beehive oil cooler, then look under the carb where the intake manifold mates to the engine for telltale signs of a leak. Check the water-pump, just under the fan hub for a leak at the weep hole. Does the exhaust blow white smoke and smell sweet? Fwiw, never let your engine overheat, they do not tolerate overheating like the piston engines do.

Running hot in stop and go traffic is often a sign of a corroded/plugged radiator, thermostat needs replaced, water-pump may be failing. When the clutch fan fails, it will fail in the constant on/locked mode, not in the freewheel mode.

It doesn't take much for the add coolant light to come on. Make sure the overflow tank has coolant and that the coolant is being sucked back into the radiator during cool down and that the rad cap is good.
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Kentetsu

Sounds like Trochoid has you covered, but there is one thing I wanted to add. I have had fan clutches fail in the freewheel mode before. A decent indication of a failed fan clutch will be if the car does fine on the open road, but overheats when standing still or in stop/go traffic.

Welcome to the forum, and hopefully we won't have to walk you through an engine rebuild on your first week of rotary ownership.

Jeezus

iTrader: (4)

Just throwing this in here, my low coolant light would come on on occasion, and the coolant would truely be low. The culprit behind this was the heater hose coming out of the firewall. Whenever the engine was building higher RPMs, coolant would start to basically gush out of the hose area. Noticed this when I revved her for a few friends. Basically, just tightened the clamp on it and I was golden.

Motto: Tighten all hoses!

RXnos1200

iTrader: (24)

check your heater core for leaks too. good luck.

Rx-7Doctor

iTrader: (13)

I keep reading that you are stating that the coolant light comes on. The light is not an indication of overheating. It is just a low level warning. Where does the temp gauge read?

If you have coolant pooling by the cap then it is possible that the radiator cap is not holding pressure because the seal is compromised. Also the level sensor sealing o'ring could be leaking. Another possibility in that area is the spot where the radiator shroud attaches to the top of the radiator. Sometimes that welded in tab will leak in that area after it detaches from the shroud.

The biggest thing here is to determine the following.
Is the engine overheating?
What is the actual cause of the coolant loss?

It has been my experience that 9 out of 10 fan clutches that fail on our cars fail to engage, not disengage.
The way to check the fan clutch for proper operation is to get the engine to operating temp. Shut if off and see if their is resistance when you turn the fan by hand. If the fan spins relitively easily then it is bad.
A stuck engaged fan will cause excessive noise and also will cause the engine most of the time depending on ambient temp to run colder.
The engaged fan will have very hard resistance in it all of time.

wanklenoob

Thanks for the reply everyone! The weekend is finally here, and I'm off work for Sat and Sun and so I delved into my problem. I read through the FSM (Thank you Trochoid!) and opened up the bonnet and ran it a bit, I noticed an actual leak coming from a hose under the oil filter. it was a good amount leaking. I also tested the fan clutch, luckily it seems to have no problem. I took the radiator cap off, and looked for bubbling. NONE I then removed the busted hose and went to Napa got a new one, (the small bendy one under the oil filter) and made sure the clamps were very tight. I replaced the coolant with a 50/50 mixture, and bled it with the radiator cap off. (that's what my crap manual said to do but I heard there is something else used to bleed it) I put the radiator cap on, and the light was still on and buzzing, I drove it a wee bit to see if that made it stop...it did not. I decided to check the thermostat, and I looked at it and it doesn't fit the description in the FSM, I found that if what I'm looking at (two wires running to it red and black behind the alternator closer to the drivers side) is the Thermostat, then some one who had the car before me put a mitsubishi one in it. (the Alternator is also from a Mitsubishi apparently.) I've been working around it all day and decided to call it a night, and work on it on Sunday. I spied another small hose leak next to the hose I replaced under the oil filter. any one have any pics or diagrams of exactly where the Thermostat is? I'm working my way across the problems and trying to eventually fix the problem. thanks for all your advice, I may post pictures soon. any other ideas would be nice! OH, and the engine doesn't really run very hot, it's about a little over 1/4 on the temp gauge. Strictly a cooling problem

Rx-7Doctor

iTrader: (13)

The FSM that you downloaded has the illustration in it.

Follow the top radiator hose from the radiator to the engine. The T-stat is under the housing that the top hose attaches to.

trochoid

iTrader: (6)

What you describe as the thermostat is one of the temperature senders. That one regulates the choke. Mitsubishi and others made many of the parts for Mazda. You might be suprised at some of the brand names on various parts.

wanklenoob

wanklenoob

I FIXED IT!! I kept fiddling with it, and replaced the thermostat, and re-flushed the system, replaced the sensor and BINGO! coolant light no longer on, and she runs smooth once more! thanks for all your help and suggestions! Everything seems to be well, and I can't wait to drive it to Seattle Next weekend! first non-local drive with the RX for me, so I'm pretty stoked. PS: I love these forums =D