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Discussion Starter · #1 ·
Hello everyone,
I just bought a 95 MX-6 V6 LS, 5-speed a couple of days ago. I love it! However, it seems that I bought it with a few problems. And I need lots of help. I have already browsed around the site (great info here!) and found how to read "check engine" error codes. So, here goes the story:

The car was sitting since February, so some of this may be due to that. It needs the trunk lift support struts changed and air conditioning charge (I'll wait till Spring for that).

1. There was no oil on the dipstick! I've added 1.5 litres of 5w30 I had around to get the dipstick to show between L and F. Phew, this was a close one! Oil change is scheduled for tomorrow AM.

2. I noticed that cooling fans are coming on in this September weather, which was strange and yesterday when parking in the garage, the fans went full speed and temp gauge started to move past middle point. I quickly shut off the engine. Checked coolant: DRY stick! I did not have coolant around, so I added about 0.5L of water, so I can get to the nearest Canadian Tire. That seems to have done the trick for now as the temp is fine and the fans are quiet.
QUESTION: I will probably need a coolant flush right away, correct?

3. Now, here come the codes that I got from the engine today:
08 - Volume Air Flow sensor (VAF)
10 - Intake air temperature sensor (IAT)
16 - Exhaust gas recirculation (EGR) system
23 - RHO2S inactivation error
24 - RHO2S inversion error
25 - Fuel pressure regulator control solenoid

So, the big question is, where do I begin? Are the above codes somehow related? Will fixing one thing take of most of them?


Disclaimer: I don't have many tools and I have never worked on an engine. My excursions go as far as changing rotors/pads, installing a sway bar, and general maintenance. :(

Thank you very much for any help.
 

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I read about half your post, and I have to say, begin by getting some coolant. I'm pretty sure water won't do anything for ya, as it'll probably just evaporate. Get some coolant, mix it with water, or get pre-mixed coolant and fill'er up.

I personally would not drive the car until then.

*Now finishes reading what else you have to say*

If they are related, I would venture to say the EGR would be causing a few of them. I believe I came across a thread of a 6 throwing similar codes and it being linked to one problem, if I happen to find it again I'll link ya to it.

I don't know though if a coolant flush is necessary if it didn't even have any coolant in it.. I think just filling it should suffice.

Does your's typically sit at middle though? Your temp gauge rather.
 

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Discussion Starter · #3 ·
I read about half your post, and I have to say, begin by getting some coolant. I'm pretty sure water won't do anything for ya, as it'll probably just evaporate. Get some coolant, mix it with water, or get pre-mixed coolant and fill'er up.

I personally would not drive the car until then.

*Now finishes reading what else you have to say*

If they are related, I would venture to say the EGR would be causing a few of them. I believe I came across a thread of a 6 throwing similar codes and it being linked to one problem, if I happen to find it again I'll link ya to it.

I don't know though if a coolant flush is necessary if it didn't even have any coolant in it.. I think just filling it should suffice.

Does your's typically sit at middle though? Your temp gauge rather.
Thanks! I actually got some pre-mixed 50/50 coolant last night and was going to fill it, but when I looked into the filler pipe, I saw there's some coolant there and when I pulled the stick again, it appeared that it now read between L and F. So, I'm not sure how much to add. Also, since I added about 0.5L of water, if I add 50/50 mix, would that now be more like 45/55 in favour of water? I don't want to risk it freezing over the winter.

Yes, my temp gauge sits at middle - maybe a hair to the right.

Thank you for your help!
 

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I forgot to top off my coolant after losing some coolant through a hose that I replaced, and within a minute, that caused my idle to raise and water pump bearing to start making noise....hopefully the same doesn't happen to you. I was only getting the noise in the winter months at startup.
 

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Discussion Starter · #5 ·
Also, I wonder since I just got the car and who knows how long those codes were on it, should I reset the ECU and then see what codes come back after a couple of days?
 

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Since you've already documented the past codes, I think that would be a great idea.
 

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Yep. some (or maybe all) of those codes may be old codes, so I would clear them (disconnect battery, press brake pedal for 10 seconds, reconnect battery, as I expect you have read). Drive it around for 5 minutes, and see if any codes come back. If they do, you might want to read about the codes here, if you haven't already seen this: 1993-1995 Engine Controller Malfunction Codes

Now, on the coolant. If the previous owner let the coolant reservoir get completely empty, it may not be enough just to re-fill the reservoir. When the engine is COLD, open the coolant filler cap next to the oil dipstick (yes, the one which says "do not open", which really means "do not open when engine is hot, and only when you suspect the car has run low on coolant") and fill it to the very brim with coolant. Open the radiator cap also (passenger side of radiator), again when engine is cold, and check that is full to the brim also.

A radiator/cooling system flush wouldn't hurt, but may not be necessary. An engine oil flush would be better value for money, after it has run that low on oil.

Check for coolant leaks (that may have caused the low coolant).
 

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check for oil leaks too!!!
 

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Discussion Starter · #9 ·
Well, I have some good news. After ECU reset, only code 16 (EGR system) returned after 2 days. So, I hope that's all I have to deal with. That requires a cleaning of the EGR valve correct?

The bad news is that the cooling fan still comes on majority of the time when it's idling at traffic lights. Also, in the parking garage, the fan gets really loud and temp starts to go up, so I just shut it off right away.

As a side note, I replaced both trunk lift support struts, so the trunk stays up now. :) However, I cannot get the hood latch to close. The safety latch holds the hood down, but when I press it, it does not lock. Looks like the part that is supposed to lock it down is not moving due to rust despite me pouring a ton of WD40 into the mechanism. :(

The car got an oil change a couple of days ago. My mechanic pointed out that there was a small leak around the oil filter, so I'll keep an eye on that, but I don't see any oil spots in my parking space. He said, he checked all fluids.


NickR: I just checked the coolant in the spots you mentioned. There's no coolant there. However, the coolant dipstick looks like it is close to full. I'm puzzled. Take a look at the pics below. Click for hi-res.

Coolant dipstick:



Reservoir next to the battery:



Reservoir next to the oil dipstick:



Should I really fill up the one next to the oil stick to the top with coolant mix?
 

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Yes, do as Nick said. What I do is open both caps and fill almost to the brim (1 inch below the brim), then start the car and if it gets lower (i.e. bubbles in the system are coming out), then fill up to just below the brim again, and as the motor warms, the coolant will start to rise itself. When it reaches the brim, cap it.

The reason your reservoir may be full but the system isn't is because one or both of your rad caps need replacing. They can be tested to see if they hold pressure, I'm assuming this pressure is needed to siphon coolant from the tank back into the coolant system.
 

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Discussion Starter · #11 ·
I read some more threads on this issue and much like suggestions here, they recommend opening the cap next to the oil dipstick and starting the engine to see if coolant starts flowing in there. Is that safe??? I don't want to have coolant all over my engine bay.

Do I then shuft the engine off and fill that cap, close and run engine again?
Is there a chance I overfill the system and have coolant spraying from somewhere?

Thanks.
 

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It's completely safe to run the engine with coolant cap off.
First fill the reservoir at the radiator and cap it, then add coolant through the cap next to oilstick. Get in the car, put HVAC on "hot" and start the car.
Coolant by the oilstick level will drop so have some handy for adding. It will also start to bubble, that's normal. It's releasing air from the system. The reason you put hvac to hot is that in this way heater core will be burped, too.
It will take some time before coolant would start overflowing. When it does, just shut the engine down and let it cool for a while. Then start again. Repeat that untill you see no more bubbles coming from the coolant.
 

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You won't have coolant spraying anywhere. My recommendation is to fill the coolant with the engine off, then leave the cap off still and start the engine and top off as necessary because it will go down a bit as air is escaping the system.
 

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Yep. I agree with PaulG and Evert. It's OK to run the engine for a minute or two with the caps off (but don't go for a drive like that!), until the engine warms up.

[BTW, Evert: there's no need on most modern cars to turn the heater on when you do this (I only learned this myself recently). On older cars, turning the heater on allows coolant to flow through the heater core, but on modern cars the coolant always flows through the heater core, and the heater controls only affects the air flow.]

eljay: Here's a short primer on how the cooling system works. If you get very low on coolant (like yours did), and you only fill the plastic reservoir, this is what happens: when you start the car in the morning, the coolant heats up, expands, and pushes trapped air down the thin hose where it bubbles up in the reservoir. When you stop the engine, and it cools down, the coolant contracts, and it sucks coolant into the radiator from the reservoir. So each time the engine warms up and cools down, a little bit of air in the radiator gets replaced by coolant. But only a little bit, so it takes forever to get all the air out and completely refill the radiator with coolant. Which is why you needed to open those two caps and fill it directly.

On the EGR: I am not an expert, but from my reading, I think most EGR codes on these engines are caused not by a dirty EGR valve, but by a clogged vacuum hole in the intake manifold, near the throttle body. You need to remove the throttle body, and clean out those orifices. Perhaps someone who knows more can provide more help.
 

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Discussion Starter · #15 ·
Update on coolant:
I followed everyone's advice filling both reservoirs and then filling the one by the oil dipstick to full with engine running. There were quite a few bubbles coming up and I added about 1L of coolant mix through this process. Before starting, the car sat for about 2 hours, but engine was still warm, so I will check it again in the morning when it's completely cold and add some more before starting it up again. I also took a close look at the caps and the seals look ok. I hope this does the trick and stops the overheating at idle.

Thank you so much for the useful advice to a newbie. I'm starting to get addicted to this forum. :)
 

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Here's a link on how to take off the tb and clean the egr port scortes's 1996 Mazda 626 on CarDomain - Page 3 . This guy mislabels the egr port on the intake manifold as the pcv port, but it gives you an idea of what to do. You can see how much the egr port is gunked up before he cleans it, and I'll post up a pic of what it looked like when I was almost done cleaning. The best way to get the gunk out is to scrape it out, it's too thick to be sprayed out. Also, when I sprayed it out (big mistake), the cleaner flowed down the port and into the egr, and within a couple of days I started getting a code because the cleaner had gummed up the egr valve and prevented it from opening, so then I had to take off the egr and clean that, which took way too long...it's impossible to get the egr tube off of the egr so scraping the gunk out of the tb side of the egr port is your best bet.

Here's a pic of the intake manifold dead on with the tb removed:


Here's a pic of the egr port that's almost fully scraped out...notice how clean it is compared to the after pic in the writeup:
 

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Discussion Starter · #17 ·
Thank you! Well, that looks like an interesting job!

Next on my list right away is the hood latch, which is not closing and it doesn't make me comfortable driving on the highway and risking it will fly off if the safety latch gives.
It looks like it's too rusted to work even after ton of WD40 sprayed there over the past week. I haven't seen a diagram to understand exactly which part is the locking mechanism that is pulled by the hood release latch inside the car, but I think I can see how it should work. Should I just replace it if it is too rusted? Is it an easy replacement?

Here's a picture of it:
 

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The plastic pieces around the latch come off fairly easily. Move them aside and get someone to get in the car and move the hood release inside the car and you should have a pretty good idea of how it works. I haven't looked at it myself, but it can't be too confusing.
 

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Discussion Starter · #19 ·
The hood latch is now fixed!
After fiddling with it for a bit thinking it's a rust issue, I took off the spring from the mechanism and was able to lock it and confirm the release cable works. I then realized that the hood hook did not go low enough to make the final 'click' to lock the release. So, I unscrewed the 3 screws holding the latch mechanism and moved it up about 5mm and that did the trick!

And here's a list of what's next:
- throttle body cleaning
- I want to fix fuel tank door since it does not lock
- clean my engine bay
- do something about small rust spots on the hood from rock chips that previous owner did not touch up right away.
- buy new rotors and pads and probably change brake fluid too.

Here's the fuel tank door. Is something missing there?


Also, can I apply something like Rust Check from CT to the rust spots to stop the rust from spreading? I figure that eventually it would be cheaper to find a hood in good shape and replace mine rather than paying someone to fix this one. :(



Thanks again.
 

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The fuel tank door: you have exactly the same problem here that I have had with my 626; I can see it clearly. See that rusted nut on the right side of the photo, with the little black dot in the centre? That little black dot is the button. It is supposed to pop out, to hold the door closed, and to be pulled in when you pull the lever inside the cabin. Spray a little oil on that rusted nut, then loosen the nut a little (do not unscrew it completely). Then tap the little black button a few times, and it should loosen up and pop out. Keep working it and oiling it.

That RustCheck stuff from CT is overpriced but works well (buy the red can, since it penetrates better). I use one large ($10) can a year, to spray spots like that on your hood, plus under the doors, plus inside the doors and rocker panels -- anywhere that rust tends to form. Make sure you attach the red straw thingy firmly; I have lost several of them inside the doors, when the pressure shoots them off the can.
 
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