Ok so I have a 83 rx7 not sure what model but i don't think it really matters what model on this subject but correct me if im wrong. Last night car wouldn't start but was getting smoke out the tailpipe, was flooding badly. I just bought the car and this is what i've been told engine overheats due to bad/leaking heatercore, doesn't overheat as long as the heaters on. I know and so did they about not overheating the car or roter will fail. note they had the moter rebuilt 7 thousand miles ago as far as i can see this is fairly true looks like new roter housings. runs good. good power. but i don't think they tuned up cap/ roters or because it has a brokin U joint (most likely the case) it vibrates when gassing and stops when u let off but dosn't get bad till after 30 mph cant really feel it to much before. but soon as u hit 30 no matter what gear shakes but stops soon as u let off. mabey the excessive vibrations dinged up the contact points on the cap. I took off cap an roter saw the T (from coil to distributer) was deformed and the rest had alot of scoring but i put it all back on and it fired right up but any other reason this could be happening.

Oh and one more question while i"m here is 75$ a good price on a good driveline?? just so i don't waist a thred to ask such a simple question.

 

Cap/rotor damage is due to the cap being misaligned, not the driveshaft. If using the heater prevents overheating, then the entire cooling system needs to be gone through. Turning on the heater is like adding another small radiator. If the engine is overheating with the heater off in winter, either one or more the following is bad: radiator, waterpump or thermostat. Good time to check all hoses and belts too.

 

So you have a broken U-joint, that hits your distributor cap?

 

Regarding the vibration. Check and make sure that the bolts that secure the drive shaft to the flange at the differential are all there and tight. Also make sure that the transmission mount is secure and not broken.

I would not recommend that you drive the car until you get this issue resolved and the overheating issue or you will destroy the engine.

As Trochoid stated you need to service the cooling system.

I would recommend replacing the thermostat at the same time also and inspect your cooling hoses. If they are extremely hard or soggy to the touch then they need to be replaced. If their is no history of maintenance of those being replaced then it's just a safe thing to buy new ones.

Also need to check the operation of the fan clutch also. To check it you get the engine up to operating temperature then shut it off. Then spin the fan by hand, there should be resistance in the fan only allowing it to rotate a full revolution or less. If it turns freely with no resistance then it is bad.

Have you check the coolant level?
Did it overheat or get hot when you drove it and if so where did it register on the gauge?

 

I added coolent before driving it home from previous owner, and have just started it once a day to well start it and **** off the lady next door. it red just under half way all the way from portland to forest grove about 50 mins going ~45 mph with heater blowing on low.

and i was wondering if the vibration was rattleing the cap causeing it to marr the contact points. not due to it hitting the drive line. Makes sence to me i blew a tranny tried to drive home with it slamming through gears hard as hell and rattleing the whole car and the oil filter got lose and blew the whole engine. extreem vibration will tear your car apart and fast. I only drove the blown transmision off the freeway about 1/2 a mile.

and yes i plan to fix it before breaking it again. I don't want to further damage someone elses break I want to do it myself.

 

If the cap's on right, it doesn't wobble enough for vibration to make for contact between cap and rotor. They are kinda notorious for people getting them on wrong, or knocking them crooked.

Of course, if you abuse anything enough, it'll break.

 

I was told by (kurt robertson don't know if u know of him) to check the fan by turning the car on letting it warm up and trying to stop the fan blade by hand. or back of a screw driver. I did this and it doesn't stop. but when i turn it off i can rotate it freely. it does seem to work still. I wll check the thermistate asap.

also radiator hoses are good and heat is present in the in and out hoses of heater core. seems to still have plenty of coolent in the radiator. probably the thermistat huh???

 

Stay away from Kurt if you want to avoid injuries.

Never ever try and stop a fan when the engine is running, what the hell was the guy thinking?


Do the test I posted please!

If the engine is at operating temperature and you can spin the fan with little to no resistance, meaning that it just spins freely then the clutch is bad.

 

I wanna start by saying thanks to rx7doctor, I got the driveshaft today,and replaced my broken one. vibrations gone!!!!!!
the overheating issue: I bypassed the heatercore, put in a new thermistat, radiator looks good, coolent tests fine, I just put it in also. not to sure about the water pump I'll take a look at that tomarrow, but i'm thinking its the fan clutch, I did both kurts test (try to stop the fan by hand with car running) and the docs test(turn it off and spin), with kurts test it passes but rx7doctors test fails. just turns freely, I've got kind of a dumbshit question should the ignition be on durring this test??? I don't think it makes a differnce but mabey..

So I'm pretty sure its bad Those are kinda spendy I did a quick search but not alot. I'm kinda short on cash at the time being, does anyone know where i can pick up a used one for cheap, I'm calling junk yards tomarrow.

And how do i check the water pump?? do i just shake it like a older domestic??

 

Your welcome.

No the ignition is not a factor when testing.


Need to know where the temperature gauge is now reading?

Also you need to re-hook up your heater core. You will not have a defrost function without the heater core and this is a very important safety feature.

There are 2 checks of the water pump.

1) Visual check to see if there is leakage of coolant from the weep or vent hole
2). Grab the fan clutch and move it side to side and see if there is play in the water pump shaft.

 

I've always turned the car off when it goes over half way. I've had alot of cars with aluminum parts, I care about my car. If i blow my engine up I at least want to be abusing it, my last car had a built top end and i replaced the timing belt with a stock oem belt, and my car ate it. ate it. it was only in there for like 15000 miles. ran like a raped ape, but blew up sitting at a red light I'd be happy if it blew while i was hammering it. it was a stroker engine with a stage 2 cam so my pistons ran into my valves, so i replaced my car with one with no pistons and valves to run into eachother. ******* dumb car....

 

are you serious about stopping it with your hand... that sounds like the stupidest thing ever.. no offense

 

One of my Auto tech teachers did it to scare the crap out of a student, but he knew the clutch wasn't warmed up so it didn't hurt him.

I ended up doing it later to scare a friend with a bad fan clutch.

But yeah, unless you know for sure the clutch doesn't work, that is single handedly the stupidest thing you can do...

 

sounds like something dave would do... i'm sorry but i would never do that

 

I questioned him when he told me to do this i didn't just do what that crazy ****** told me. I watched the rotation of the fan to duble check and made sure my fingers where going the right direction I stuck my hand in their slowly till the fan was bouncing off the tips added a little pressure to try and stop it and no luck. cant stop it. I'm still sure its bad though. But I'm confused on why if the fans moving and blowing plenty of air. enough to blow tools and boxes off the fenders why is it overheating. . I think this is the first engine driven fan i've had on a car. most of my previous cars were late models 99 2001 2003 no I lied my chevy luv had a fan on the engine. but it worked... why doesn't it work if its moving air its doing its job... So i think their may be more to the overheating issues.
someone please explain

 

the fan only brings air in, if your radiator is bad or your thermostat or any hoses that would cause over heating. if the omp isn't working then you'll overheat as well... if your oil cooler is broken. expect overheating o.O

 

You need to verify what the actual temperature is. You may have a faulty sender unit or the gauge is bad.

 

didn't he say it was going into the red?

 

No, it was his misspelling that caused you to think that.

it red just under half way all the way from portland to forest grove about 50 mins going ~45 mph with heater blowing on low.

 

Okay, I think I figured it out. the hose clamp was broken on the shorer hose on the botom where it hooks up to the metal tubing. I replaced it Heatercores still bypassed, but I bought a new hose, I'm going to put it back in. But mabey it was spraying through the holes for the heater core, and flooding into my passangers floor board??? Well I guess I'll see tomarrow. but It seems to of quit the overheating, but I havent driven it around just had it ideling trying to see if it overheated. the hose was leaking due to hoseclamp, could of that been the issue all along???. I do have a loose wire just hanging. It comes from the front plate has a plug on the loose end. I have another post about this question someone said it was a oil level sensor and it looked like I was missing the oil temp sensor? I'll post the pics... The pctures were taken from drivers side of engine. Also first pic is from the top other 2 from the botom.

 

83? so that means you have the honey comb oil cooler.

When the heater is on, coolant that goes to the oil cooler is routed to the heater. Ergo, if the car doesn't over heat when the heater is on, then your honey comb oil cooler needs to be flushed.

Or they screwed up when installing the rebuilt engine.

$75 for the drive line? You mean drive shaft. I payed $125 for a junk yard one. A machine shop can press out the u joint journals on the 83 model. Other years are easier to rebuild.

Oil level sensor is a good guess. Local auto parts stores have them for like $8. I broke mine when installing a rebuilt engine.