rookieplayer

as the title says, I recently bought an automatic '86 GXL with 75k miles for $2k. it runs great but i do have a couple of questions...

1. i read that the transmission is 'notchy' and i think i understand what that means. the only problem is when i'm coming to a stop, the car makes a weird shifting sound and lurches forward. besides this, the car shifts up and down perfect.

2. the car tends to run a bit warm, about half ways on the temperature gauge, when i get up to higher speeds (45mph+). i've read that with a missing underbelly pan, the car will run hotter. i've been browsing the forums and searching for pictures as to what exactly it looks like and i've yet to find one. from the descriptions i've read, i can say i don't have one because i can see the oil cooler and the radiator when i look underneath my car. i'm just wondering if someone can post a picture just for visualization.

3. lastly, the car was leaking transmission fluid from where the speedometer cable (i think that's what it's called) connects. iirc, it was a 17mm hex tip and lose so when i tightened it, it hasn't leak so far. anyways, if i unplug it, will transmission fluid flow out similar to when one takes off the oil drain plug? should i put some sealer on the thread to prevent leaks in the future?

thanks for reading and to those who'll post answers

Boatguy

The belly pan you need goes from the bottom of the radiator to the front of the oil pan. If you look down inside the car at the battery and can see the ground, you don't have the one you need.

rookieplayer

i guess this means i don't have one.

another thing is the car's idle is kinda off as well. when i press the brakes, the RPMs drop a bit. the RPMs also "bounce" a little when idling. i've read up on this and it's generally the TPS and BAC, IIRC. does seafoam work or do i have to use carb cleaner or something else?

thanks again.

rookieplayer

alright, so another few questions, is the S4 bellypan the same as the S5 bellypan? i'm thinking about heading to a few junk yards to see if i can salvage one...

also, has anyone made their own bellypan? i was thinking of a back up plan of buying sheet metal from home depot and fabricating my own.

thanks for the inputs...

Boatguy

I would guess they are the same. I've seen them on ebay from time to time. I don't see why you couldn't make one. They're not structural, just manage air flow.

rookieplayer

that's the odd part...i went to home depot and bought a few aluminum sheets and fabricated my own which took a few hours. however, i noticed my car was running hotter with it. it was attached to the front of the grill and going right behind the radiator where it appears the actual pan would bolt in since there's 3 threads there.

i was talking to my dad about it and he said it may be causing drag instead which would make sense since the car wouldn't cool down at all on the freeway.

Zero10

If you are running hotter with a belly pan, and it is overheating on the freeway but not at idle you probably have a clogged up radiator. I am going through the same thing with my car right now, it will get well past the 1/2 way mark when on the highway if I am going up the slightest hill.

Boatguy

Could be a clogged radiator. I'd blast it with a strong hose flow or pressure washer. My belly pan is plastic and goes from the base of the grill all the way to the heavy metal frame member just ahead of the oil pan.

rookieplayer

thanks for the tips, zero and boatguy. i'll definitely check into that since i've been wanting to flush out the old coolant anyways.

also zero, i'm having the exact same problem although with the fabricated pan, my car would go above half and since i've taken it off, it's about halfways on the freeway. well, whenever i go above 50mph. do you have a belly pan on though? i still want to get one for mine...

BomberMan

iTrader: (4)

it's like trying to diagnose cancer from a sore throat. The temp gauges on these cars are far from accurate, so I wouldn't put much stock in the factory readings. I'm quite interested in the self fab undertray however. I might give this a shot myself at some point in the near future.

All of your transmission woes can be solved by switching to a manual.

rookieplayer

i get paranoid about the temp gauge going above halfways. it got to about 3/4 up yesterday while going long hill with 85-90 degree weather and stood at about halfways at idle. it went back down to 1/3 when i parked it at my house.

zero, is your car still having similar symptoms?

rookieplayer

so i was looking at my car's setup and it shows i also have an electrical fan and it'll turn on when the water thermo switch is unplugged or I'm guessing when the A/C is turned or it gets above a certain temp. I've never heard it, or seen it go on only when I've unplugged it or used the A/C. Is it possible that my gauge isn't working correctly? Anyone know when the electric fan comes on or does it come on at a certain temp?

Zero10

My car has no belly pan right now and is having a similar issue, at higher speeds (120km/hr+) on the highway it starts to run hotter until I get nervous about it and slow down, or when climbing long hills the same thing happens. When left idling it never overheats.

I will be installing the belly pan and seeing if that helps with the problem but I am pretty confident the issue is a plugged radiator. If the belly pan doesn't fix it I will remove the fan and shroud then use a temperature gun to check for cold spots on the rad. Hopefully something will show up.

rookieplayer

i changed the coolant in my car and it still does the same thing, although i have a lot crap in the front of the radiator...well it looks like a radiator but it's in the middle of the radiator and the oil cooler. it appears to be some sort of protective radiator looking thing. i should take my shrouds off and give it a clean...no belly pan still for me though...

Zero10

... the a/c condenser?

Belly pan didn't fix my problem, I'll be flushing the rad hopefully sometime this week. I almost never drive the car so it may take me some time to get to it

rookieplayer

yea that's it! anyways, upon further investigation, i believe it's a clogged radiator. the top of is pretty hot, i can put my hand on it, but after a few seconds, it gets too hot. on the bottom, it's very cool. the area where the lower radiator hose is located is warm like the top. i don't think i should be that cool on the bottom....

Zero10

On mine I can run it without the fan installed, and after it gets up to temp the top of the rad is scorching while the bottom is barely warm. With no airflow over the rad the temps should be pretty consistent (maybe 10-15*C lower at the bottom, not 50*C+ like I am seeing) so I am pretty confident I have a plugged up rad.

I picked up a bottle of prestone super flush and plan to use that according to the directions and see what sort of difference it makes (I'll measure it with my temperature gun to see what I get). If that isn't good enough I'll remove the rad and CLR it and see if that fixes it. If the CLR destroys the rad then so be it, without trying it my other option would be to replace it anyways so for a couple bucks it's worth a try.

If you are undertaking a similar process I recommend removing the rad and washing out the fins of the A/C condenser and radiator.

Zero10

Since you were experiencing something pretty similar to what I was I thought I should post an update to my situation:
I set to work on the overheating problem today, assuming a plugged up rad I drained it, flushed it once with water, filled with the rad flush chemical then ran it for the prescribed time (during which it started to overheat and I had to cut it short), then flushed fully with water. At this point since it overheated during the flush I decided to pull the rad and clean it with CLR. I removed it and tried running water through it, it ran through with no problems, bringing almost no deposits or colors with the water. I flushed out the fins which were only slightly dirty and flushed out the fins on the A/C condenser, then decided to keep looking since none of these seemed like a big enough issue to cause overheating when driving on flat ground at 70km/hr (low 4th gear). I removed the thermostat and brought it inside, placed it in a pot of water and set it to boil. The thermostat was marked 82*C, and I let it go up to 95-96*C (boiling point here is ~96*C) and it never opened.

I spent ~5 hours chasing down a radiator problem that didn't exist, the only problem was a thermostat that wouldn't open....

Check that first. I've seen 5 thermostats fail in past cars of mine and they have all failed open, causing delayed warm-up and low operating temperature. In 10 years of car ownership and 400,000km I have never seen one stick closed... I guess I should have checked that first.

rookieplayer

ahhh thanks zero. i did flush my radiator and all the water came out clear too. i'll definiately replace the thermostat. did you buy yours online from mazdatrix, atkins, rx7.com or did you get one from a dealership? i was reading some threads about how mazdatrix doesn't have oem or something like that. i was thinking rx7.com since it's $15.95 and i'm guessing it comes with the gasket since it says it's sold separately with the 89-95 model RX7s.

and finally, is it running where it should be?

Zero10

Due to a time constraint I had to buy a generic one from a local parts store, however I have an OEM one on order from a local dealership and will swap it out when it arrives.

I got the chance to put 70km on the car over the weekend including in auto-x in 25+*C weather and the needle never got above 50%, spending most of the time at 40%. I left the belly pan off due to a lack of time. I'll put it back on later but so far it seems to be running at just the right temperature even without it.

rookieplayer

that's awesome zero! glad you figured out your problem. i also have good news because my thermostat and upper/lower radiator hoses arrived today. i put both thermostats in water and let it boil and guess what? the old one was opening, but not even as fourth as wide as the new one! it wasn't getting enough coolant.

so for those who have heating issues, check your thermostat!!!

Zero10

Glad to be of some help, and its great you got yours fixed up There was a problem with ordering my new OEM one and it didn't arrive, and the aftermarket one is working properly so I'm probably going to leave it in there a while. I only drive the car to/from the track and during auto-x events so it gets maybe 50km every 2 weeks if even that, and whenever it is driven I am paranoid about all my instruments so I'm confident I would catch a problem before it became serious. The only thing I find concerning is the opening in the center on the aftermarket thermostat is about 1/2-2/3 of the area of the OEM one.

Did your old thermostat open at the same temperature as the new one? Or did it open at a much higher temperature?
I suspect mine was working properly when I bought the car as it didn't start overheating right away, but about a week after I started driving it every day (just trying to rack up the miles to give it a shake down) it started overheating on me just when I was going up steep hills at low revs, then it started overheating even on flat ground. I think mine started opening later and later until it didn't open at all, it sounds like yours was well on its way down that path too.

rookieplayer

they're both set at 82C and they did open at +/- 5C but the old one wasn't opening all the way. i'll see if i can get the pictures up. it still gets up to about halfways when going up the really steep hills around in my city. i'd guess around 20-30 degree hills that go up for about half a mile. it comes back down pretty quick too and when i was booking it on the flats, the gauge was about 1/4-1/3.

the only problem now is i don't think i put enough RTV on the temp housing. beads of coolant are coming out when i brought the car back from a drive although the bolts could've been tightened a bit more which i did.

Zero10

Did you use a gasket with the thermostat or just rtv?
I got an aftermarket gasket for mine, it had adhesive on one side so I applied a skin coat of RTV to the other side, then did the bolts finger tight, let it set for an hour then torqued them down. I couldn't find a torque spec in the FSM so I just did them by hand. They weren't very tight, just palm on the head of the ratchet tight. So far I am leak free with mine.

rookieplayer

i got a thermostat from a dealership and it did have the same gasket you're describing. i didn't put rtv on the sticky side of the gasket, but it looks like it's leaking from that side hahaha...i tightened mine to arm strength and so far it hasn't been beading. it does look "wet around the top but i'm very **** about stuff like that so it's probably nothing to worry about.