Siggi G

hi, i have a rx-7 twin turbo '94 and it's always overheating? any ideas what it could be? the engine was restored in 55t miles and the car is now only in 68t miles. any ideas would be great.

thanks

1revn3rdgen

iTrader: (27)

Check the hoses,rad.,for leaks.I could never remember the name of that black plastic bottle i thinks it's called the ast but check if it's also leaking or you might need a new cap for it.

Siggi G

i will do that. but the car only overheats if im driving in the 5th gear! sometimes in 4th gear. it's very strange.

andre sinclair

iTrader: (36)

Well, well, where do we begin. If you use common sense, you will notice that the operating temp. is between 180-195 degrees. So If you cruising on the interstate in 4 and 5 gear and notice the temp. gauge raising, i `ll think circulation could be a problem.

check the following:

1. check for leaks and pressure the caps. AST/water filler neck
2. check to see if the reservoir and AST has enough fluid/coolant
3. possible thermostat not opening fast enough...replace
4. Cooling fans not cycling throughout the speeds...low/med/hi.
5. clogged radiator

Let us know your findings.
Andre

Siggi G

thanks andre. i will do this as quickly as possible. but i alredy checked the thermostat. it's was fine i think. we removed it just to see if the car would overheat again. and well.. it overheated.

andre sinclair

iTrader: (36)

start the car...run it until it gets hot. After it starts to overheat turn on your heater in the car. remember not the A/C but heater. Put the blower speed on the higest setting/speed run the car for a while with blower on and if the temp. drops replace the radiator.

Let me know
Andre

P.S. verify that the radiator fans are working.

neit_jnf

iTrader: (17)

maybe you have air in the system?

dgeesaman

iTrader: (7)

How do you define overheating? Are you using an aftermarket temp gauge, the temp on your aftermarket ECU device, or the stock temperature gauge? At what temperature? Is your oil level full?

Because if you're repeatedly overheated according to the stock temperature gauge, your engine block could be as wavy as a potato chip.

The other posters are right on: Fans, Flow, and Full. So first check that the fans are both running and the fan relays are good (FSM page E-13), then make sure coolant is flowing freely (not a clogged rad or stuck thermostat, and maybe replace both AST and water filler neck caps to be sure they're holding full pressure. Last, check for leaks and be sure the system is well burped. If you're still at a loss, I'd change the coolant temp sensor (E-17).

In the USA, Autozone will loan you a coolant system pressure tester, which I strongly recommend for checking the system.

Dave

Siggi G

the stock temperature. it reaches red. and it has gone over it maybe 2-3 times. im planning to take the engine apart and change everything. since im new in this about rotor. what exactly do i need to replace if i take the engine apart? all info would be great.

thanks for all you're help

dgeesaman

iTrader: (7)

Yeah, if you've overheated on the stock temp gauge, you've really cooked it. It may have been converted to a linear gauge behavior, but still I think it's bad. Normally a stock gauge should never get to horizontal, much less to the red mark.

You're in line for a complete rebuild, and probably new housings since they may have warped. Run your searches on "engine rebuild" and you'll have a lot of reading. I wonder if anyone in Iceland can do the job - didn't you say before your FD is one of the only ones in the country?

I recommend downloading the FSM from www.iluvmyrx7.com and buying the rotary aviation engine pull and rebuild videos. If you do it on your own you'll need this at a minimum.

Dave

Siggi G

it's one of 5 rx-7 in iceland. 3 of them are on the street's but the other 2 really messed up after crashing.

well my best friend is a learned mechanic so i think i'll have his help rebuilding the engine.

but tell me dgeesaman what do i need to buy to rebuild my engine? seal's and bearings? very sorry about my english. i talk it much better than i can write it.

dgeesaman

iTrader: (7)

Your english is very clear.

http://www.rotaryaviation.com/Books_videos.htm

Buy the last two videos on this page, they are excellent. Your friend will find that it's easy with this kind of instruction.

I can't say for sure what parts you'll need, since you should replace all seals and gaskets and replace only the 'hard' parts that require it. First, you'll need a new engine gasket set - either Mazda or aftermarket. When it's all apart, you'll need to check all the 'hard parts' and order replacements for them. Do not skimp - this is a detail-intensive project and you want to do it right, and do it once. It will take weeks.

Gasket set: (just one of many out there) http://www.rotaryaviation.com/overhaul_kits.htm

Run a few searches on 'engine rebuild'. Several people have done it DIY (do-it-yourself) style and done well. With your friend's help, and hopefully his access to proper tools, and a little luck, it should be a rewarding little adventure. https://www.rx7club.com/showthread.p...43#post3770343

There are other options - buying a used motor or remanufactured motor. Then you just swap them in. Used motors are always a crapshoot, remans are generally good but a few lemons exist. With a reman check on the warranty. Hopefully you can install a reman without paying crazy freight charges or voiding the warranty. The upshot is you can actually get it installed in just one (busy) weekend. Maybe you can score the used motor from the wrecked FDs - it would be cheap and fast.

Dave