DHALL

At last the time has finally come. I have been on the search for a FD for over 2 years now, as some of you know because I was at the BBQ last weekend (my name is Dustin for those of you I spoke with) The details are as follows. I saw the post last night at 3am and it had just been posted. I was in disbelief after I read the post. He was online, and he was from MD. We spoke at 330am, and I told him I would be there in the morning. So I got my friend Robbie(who helped build Demetrious' race car) to give me the go ahead if everything looked good. He did and I bought it. I have it at my house and couldn't be anymore excited. My question is this. He sold it for cheap because the car runs but began to overheat, so he took it to his mechanic. He replaced the thermostat, and that didn't work, so he told him that it was the water seals in the motor that was causing the overheating. What should I replace before assuming that it is definately the motor? Demetrious told Robbie that I should replace the water pump, and there is a hose missing from the overfill cap to the ast. Is there anything else that I should replace before ripping the motor out? I am so excited I can't see strait. Also if Rikki reads this I was wondering if maybe you could give me a call at 410-570-1341, if you have time so that I can talk to you and hear your opinion. Well here is the link guys please check it out and tell me if you think it was worth the two year wait.
Thanks,
Dustin(FD owner at last)
https://www.rx7club.com/forum/showth...threadid=95102

Kiflin

Congrats on finally getting the rx7, I also live in maryland, in harford county, I will most likely pick up my 94 rx7 this friday or saturday. Possibly we can meet or such and ride around.

mine is also red, with black leather interior

saxyman990

Dang! Nice car man, looks like you got a heck of a deal with that thing considering all the shizz that it came with. Looks like its in gorgeous shape too! Hopefully that overheating thing won't be a big problem for you.

So basically, in less than 24 hours from seeing the post, you own the car? You sure as heck don't let any grass grow under your feet, eh?

Welcome to the club!

Rob

Jonesboro

Don't just "rip out the motor". Get a qualified rotary expert to diagnose the overheating/suspected seal problem. Don't just rely on what the prior owner told you.

atihun

Are you sure about this?

If so, then this may be the cause of the overheating.

The hose is supposed to allow coolant expansion overflow into the overflow tank. If this is the hose, and it's missing, it will dump coolant out of this location and pull air back into the ast when the engine cools down.

Good luck.

diablone

iTrader: (2)

Congrats! Hope I find mine soon as well.

DHALL

anybody have any suggestions of what else to check? Thank you in advance.

pomanferrari

iTrader: (1)

if you have time so that I can talk to you and hear your opinion. Well here is the link guys please check it out and tell me if you think it was worth the two year wait.
Thanks,
Dustin(FD owner at last)
https://www.rx7club.com/forum/showth...threadid=95102 [/B][/QUOTE]


Hey Dustin, I thought about buying that car too but the wife said I was asking for a divorce. Congrats! Now I will have to report you to the authorities as you have just robbed some naive foreigner.

What are the symptoms?

Here are the symptoms with a definitely blown motor:

1. coolant buzzer in the morning; fill, drive all day, park overnite, coolant doesn't get pulled back;
2. hard to start;
3. white smoke on the passenger side compartment during start up;
4. smoke screen while driving.

Symptoms of my current motor:
1. coolant buzzer in the morning; fill, drive all day, park overnite, coolant doesn't get pulled back;
2. runs great for the last 800 miles;
3. no overheating at all.

I can't figure out if my current motor is blown or not but I have replaced t-stat, radiator hoses, heater hoses, caps, but nothing help at pulling the coolant back into the engine. I even did a CRC block weld.

As long as it doesn't overheat, keep driving it; carry extra coolant in the car and your local AAA tow truck number.

If I replace my motor, I'll take digital photos of the whole process and post them.

pomanferrari

iTrader: (1)

One other thing. With that kind of mileage, definitely get a Mazda waterpump. Buy it from Malloy. Mine was replaced at 68K and it had cavitation damage.

While you're at it, replace the two lines going to the turbos, the lines from the throttle body to the engine and the engine to the pump.

DHALL

The owner said that the car overheated so he took it to his mechanics and they replaced the tstat, that didn't work so his mechanic said it was bad water seals in the motor. He was moving back to Thailand so he didn't want to replace the motor. What should I do? I am going to put the tube from the tstat back to the ast, and then see what happens. I am afraid though to let it overheat, in case the motor isn't bad and it is just a coolant issue. What would you guys do if you were in my place? There is no smoke, no problems starting it, and what does the coolant buzzer sound like? Is it a constant buzz, or is it like the noize when you put the key in the ignition? Thanks for all of the advice.

pomanferrari

iTrader: (1)

aReX-7

iTrader: (3)

I really doubt that your water pump could be the problem. Yes, a stock waterpump does cavitate above 7000 rpm, but I have never heard of "cavitation damage" to the water pump in a car.

I would start by having your radiator flow tested. Also, check the small water hoses leading to and from the turbos, as well as the coolant lines going to the throttle body and back.

I just did this to an FD that was consistently "overheating" and I found that his radiator was full of rust and junk, and so were all of the small coolant lines. I completely backflushed the system (you must flush the system in the opposite direction of coolant flow) and replaced the radiator. Use a 50/50 mix of coolant and water. Problem solved.

If you are overheating the cooland due to excessive blow by (bad water seals) there should be lots of bubbles coming to the surface of the cooland in the water neck when the car is running. Remove the cap on the water neck (not AST) and start the car. As it warms up and the thermostat opens, you will probably see bubbles coming up if the motor is bad. Also, you can take your coolant to a shop and have it tested for hydrocarbons to test for bad water seals.

Good luck.

Jeff

DHALL

Figure this out!!! The FD that I just bought yesterday for a cheap price because the guys mechanic said it needed new waterseals because it was having overheating problems, well it isn't overheating. My friend who went with me to get it said it may not be the water seals at all. He said that there was a missing hose from the AST nipple that releases the water back into the overfill resevoir. He said that maybe because it was missing that it was losing the water and sucking back in air, causing it to rise in temp, and then getting air bubbles. So he told me to let it idle and then see if the temp rises anywhere near half way, and it didn't. And then I decided to drive it around my neighborhood, and the temp never went above just below the halfway mark. But when I got it back and parked it, it was leaking water from under the driver side. So I popped the hood and the nipple on the AST had blown water all over under neath the hood!! So does this sound like maybe because the hose isn't recirculating back into the overfill tank from the AST tank that after a while of the car driving and blowing water and coolant all over that this was the cause of the overheating, and since his mechanic replaced the tstat and that didn't work he just mis diagnosed the problem? Please I hope this is the problem, cause if it is I just got a really good deal.

pomanferrari

iTrader: (1)

Sounds like your engine is pressurizing the cooling system and blowing the coolant out.

DHALL

What does that mean? Is it maybe because of the missing tube, or is it the motor gone bad? Come on guys make me sleep better.

RX7Elmo

it seems that your engine is heating up the coolant or pressurizing it, and then it for some reason isn't returning or it's staying in one place and then it just overflows. I don't get what you say by saying water from the nipple come off. Did the nipple actually break? did the hose come off again? Also, the stock temp gauge isn't linear and it does stay in one place for a long time. Pressure test your coolant. Doesn't sound liek a bad o-ring.

DHALL

The hose still isn't on there, I am putting it on today. The guy that I got it from emailed me and said that the hose was on there when the car started to rise in temp. His mechanic put a new tsat on the car and it didn't work so he took off the hose and did a pressure test and said it needed new water seals. Do you think that this is the definate cause? Could there have been an air bubble? Cause I drove it yesterday for like ten min. after letting it idle for like ten min. and the temp never went over normal. Are there any other potential reasons that this may have happened?(the temp rising)

atihun

DID YOU NOT READ THIS POST EARLIER?

atihun

Um, that is normal. That's why you have the overflow tank. Without the line from the AST to the tank, you have no way to recover the coolant once the coolant cools down and takes up less volume=pulls coolant back in from the overflow tank.

If you are talking about gas blowby, then I appologize. Yes, if you have a small crack or hole in the coolant o-ring, there will be much greater pressure in the combustion area pushing gases through into the cooling system thereby pressurizing the coolant, adding in extra "air" and when the engine cools, it will not be able to suck back in all the coolant it pushed out.

Add in the AST line first and see what happens. If you find that your overflow tank gets coolant in but the level doesnt drop just keeps rising, then probably you have a massive air bubble in the system, or your coolant o-rings are shot.

RX7Elmo

if worse comes to worse i suggest you read that thread about using CRC weld or something from pepboys to fix the o-ring problem. I think it's a page back.

danny