Coolant Calamity
 

If you want to see more of the saga that is my FD life, he's my last thread (fully resolved).

https://www.rx7club.com/3rd-generati...mlins-1121974/

Today, I started it up to drop it off at a body shop to do some welding work (repairing the floor pan). After a while, billows of white smoke started coming up from under the hood.

Turned it off, inspected, and thought I found a coolant leak at the hose clamp feeding the turbo. Shot of the engine bay:

https://cimg1.ibsrv.net/gimg/www.rx7...527a370a51.jpg

I planned to pressure test the coolant run, so I pulled the filler cap and thought this was interesting:

https://cimg7.ibsrv.net/gimg/www.rx7...3d9771d219.jpg

I'm by no means an expert on FDs, but I work on enough cars to think that sludge buildup should concern me. Also, is this cap right? I don't see an AST on my car and I thought I needed a 13psi cap with a spring (off the FC I think).

I wiped the sludge off, here it is:

https://cimg0.ibsrv.net/gimg/www.rx7...890a42935f.jpg

I put some distilled water in till it was full, hooked up my pressure tester, pumped to 5psi, and instantly saw the problem:

https://cimg6.ibsrv.net/gimg/www.rx7...d5adcdd0df.jpg

It's really hard to tell here, but there's a razor-thin slice in the coolant hose I'm holding. I think it's been like this for a while and it just decided to finally break with the heat cycles and the temps rising.

Here's shots of my filler neck, just to go with the engine shot at the top:

https://cimg2.ibsrv.net/gimg/www.rx7...3d212fc468.jpg
https://cimg3.ibsrv.net/gimg/www.rx7...ce8aafc231.jpg

So, here we are. A couple things:

1. Am I right about the cap? Or do you see a reason mine shouldn't have one?

2. I'm going to do some searching, but if you know a source for those coolant lines to the turbo and the DEI wrap, please post it up so I can go buy. I need to buy ASAP and get this repaired.

3. Anything else based on the pics that I should do/have? I've read about a tensioner for the belt when it's built like this. Really any thoughts/input, I'm in so deep with this car I'm not turning back now.

All help/input is appreciated.

The residue looks to be hylomar, which is the sealant you use for the water jacket seals. Probably just used a bit much.

1. You've had an AST delete - pressure cap then has to go on the filler neck.

2. Water lines can be rubber, braid or hardline, latter two might require removal of stock fittings in the waterpump and conversion to AN male. That black fireshield, if it's hitting the turbo housing....or even if it's close it will die. Don't like zip ties on coolant system components, I'd look at a hose clamp there on the overflow.

3. Idler pulleys can bring their own problems, there's a few threads here. Water pump pulley, is it aftermarket underdrive? Doesn't look like huge contact surface, but if it runs without slippage or cranking on too much pressure on the belt, you might be ok already.

Definitely looks like hylomar and RTV. I wouldn't sweat it.

And don't be dramatic - this isn't a calamity. A calamity was when my FC blew the coolant seals in several places at once and would blow 2 gallons of water out the exhaust in 5 minutes.

2. Agreed, but to be fair stock overflow doesn't have any type of clamp on it. Not under pressure.

3. OP - Look at the pineapple racing idler pulley kit. Pineapple and Banzai Racing sells them. You need to have an idler pulley on there with the air pump delete or you can damage the front main engine bearing and/or slip your w/p pulley.

I would also just go through the coolant lines on your car. I can see the radiator hose that goes to the thermostat housing has crusty coolant residue around the top, looks like it's been seeping.

The hose going to the thermostat housing nipple that normally goes to the AST is an aftermarket hose and doesn't look to be in good shape.

The stock coolant hoses are the best you can use for the car, they are a metric size that fits right and Mazda uses a good high-temp rubber. Any hoses that are weeping, rough looking, or sketchy should be replaced with new hoses. The metal pipes they attach to should be cleaned up with a Scotchbrite pad or something to get the old crust and residue off so you have a solid rubber to metal connection. Use stock spring-type hose clamps wherever possible, they don't bite into the hose and expand and contract with heat but retain the same clamping force.

20+ year old coolant hoses are just waiting to fail.

Dale

While you are at it, may as well upgrade the AST elimination kit to our billet part. Air Separation Tank (AST) (93+ RX-7)

https://cimg6.ibsrv.net/gimg/www.rx7...c9a4ed6cb0.jpg

The thing I don't know is, should I be applying it on there when installing the filler cap? I've just never seen that before.

What worries me about this cap is, it has no markings on top (no idea what pressure it's for) and doesn't look like others I've seen pictures of. Here's a side shot. I thought the proper caps have a spring in them. I'll buy a proper one for piece of mind if there's one I should buy.

https://cimg9.ibsrv.net/gimg/www.rx7...1826cf8790.jpg


That's worrying. I thought the DEI wrap was supposed to be direct-contact capable. I also didn't build the engine, so I assumed this was all right. A bit disappointing but far from the first with this car.

Thanks, I'll replace them all, hoses and clamps. Three questions.

1. Can I use the stock Mazda hoses with this single turbo setup? I want to know if the routing of the hoses will be a problem since (I assume) it's not the stock position.
2. It seems real tight to get the turbo hooked up. What should I do to avoid touching the housing with the hose? Pic below of turbo.
3. Last, are stainless steel screw-type hose clamps from the plumbing section at Home Depot suitable? Or do you mean these: https://contentinfo.autozone.com/zne...13400/image/4/

https://cimg6.ibsrv.net/gimg/www.rx7...5a1294ef40.jpg


Ya know what... I'm gonna order that. It's a nice looking piece, and well, why not. Expect an order today. =)

I'm not sure what this pulley is or what it should be. It looks a bit like a Greddy (in color) but I don't see a second pulley from the same kit. Here's a closer shot. I'll do some reading about the idler pulleys. Whatever I need to make it reliable.

https://cimg1.ibsrv.net/gimg/www.rx7...cb136d8152.jpg

The hylomar or RTV is from the internals of the engine build, its excess that was swept away by the coolant. Should not be applied to the cap.

Factory mazda coolant hoses will not work with your single turbo setup. I'm not knowledgible enough to help with what you should use there, sorry.

The pulley setup you have is a Greddy or Greddy style. From the factory the car came with 2 belts. One to run the a/c and power steering pump, and the other to run the water pump, alternator and air pump for emissions. Your car has had the air pump deleted so the belt only runs the alternator and water pump. This setup is not ideal as the belt does not use much surface area of the water pump pulley allowing possible slippage. As another user mentioned, pineapple racing and full function engineering offer idler pulleys with brackets that allow the belt to route around the alternator and water pump pulleys similar to the OEM setup to eliminate the slippage or over tightening concern. I believe you will need to replace the water pump pulley with an oem pulley to use these as the greddy is bigger (not 100% on that)

Thanks, that helps a lot. I didn't think it should be there deliberately, so I'll make sure I don't do that.

Thanks. I'm also guessing I'll need to check clearance to see if I can use an idler pulley with the single turbo where it is. Agreed?

Yes you will need to check for clearance for the new idler. Pineapple offers 2 versions, one being the big turbo. https://www.pineappleracing.com/fdidlerpulleykit-2.aspx

I personally have the full function kit which is very nice. You can probably look at pictures and get a decent idea for clearance.

Use the BT idler kit. I have a water pump Greddy style and the BT idler clears it fine.

Yea OP beat me to my edit with his reply. I was thinking the greddy pulley was much bigger to work as intended but wasnt as sure as I wrote it

Quote:

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Originally Posted by alexdimen

Agreed, but to be fair stock overflow doesn't have any type of clamp on it. Not under pressure.

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Stock does have the usual mazda spring clamp, but I suppose this is after the pressure cap now as configured.

Quote:

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Originally Posted by Nemo128

That's worrying. I thought the DEI wrap was supposed to be direct-contact capable. I also didn't build the engine, so I assumed this was all right. A bit disappointing but far from the first with this car.

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You'd have to look up the specs, but similar brands can only go a couple hundred C in direct contact, they can go considerable more nearby, but the silicon sleeve eventually hardens and cracks, especially that close....I'd be trying to improve routing. A mate's car actually had the stuff catch on fire years ago on a high boost race car, but imagine there was a bit of oil in the fibreglass fur inside to cause that!

Quote:

---

Originally Posted by Nemo128

What worries me about this cap is, it has no markings on top (no idea what pressure it's for) and doesn't look like others I've seen pictures of. Here's a side shot. I thought the proper caps have a spring in them. I'll buy a proper one for piece of mind if there's one I should buy.

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Spring is probably in the centre column rather than external, if you had a stock AST, mityvac or similar and blocked off a port, you could see what it takes to lift off the seat.

Thanks all. Last thing I need to figure out... what to replace the hoses with. Once I know what to use, should be simple to do.

The plan for today is to drain the coolant and pull all the hoses off to see what they are. Then hopefully find like replacements. Once the work day is done.

I'm not sure what to use on the single turbo coolant hoses unfortunately. Having some sort of heat wrap type deal would definitely be a necessity since it's so close to the turbine housing.

Heat wrap is for radiant heat, not for direct contact. Pretty much anything that touches or can touch (due to engine vibrations) a turbine housing is going to lose the battle over time. That joker is HOT. May also be worth looking into re-routing the hoses in some fashion.

The upper radiator hose, for example, I would replace with a new OEM hose. Also the same for any other hoses that are flaky.

Dale

Here's the damage. Fire wrap was burned right through.

https://cimg0.ibsrv.net/gimg/www.rx7...89ea785f02.jpg

Hose was beyond just razor slit.

https://cimg5.ibsrv.net/gimg/www.rx7...3495054df0.jpg

And the turbo visibly has the burned wrap on it.

https://cimg8.ibsrv.net/gimg/www.rx7...c4952f6f4b.jpg

Now the research on the way to do this myself the absolute right way and avoid this completely in the future... the money pit continues.

EDIT: Seems like these things would make this better.

1. Replace banjo fitting on turbo with AN (looks like the second one is already AN)
2. Modify the water pump housing for AN fittings.
3. Run hardline (or whatever is recommended) from turbo to water pump housing

Thoughts?

Hardline would be nice. Big thing to take away from this is VERY little survives direct contact with a turbine housing. That could have been the best high heat hose out there but it's not going to take the crazy temps that turbine housing will put out.

Buddy of mine blew his engine with the vacuum line going to the MAP sensor (on an FC) touching the turbine housing and melting a hole. ECU thought he was running less boost, engine got less fuel, boom.

Good thing is you caught it before it was a HUGE problem.

Dale

Which is very upsetting. The money I spent on this build (to the tune of $19k), something like that seems like quite an oversight for something that could have been so simply to resolve. It's not like I minded spending the money. I basically threw money at every recommendation and accepted advice with no questions asked, at great expense. Lesson learned though. I'll be looking for a new place to take my money.

What's the name of the shop?. IMO people should not be afraid to report poor workmanship. Reputation is very important to a business' liveliness and if they know they may loose business over shoddy workmanship, that may adjust their behavior.

And, if they respond along the lines of "that's what you paid for", that a BS response since they never should have taken your money for this type of installation to begin with.

It's hard to say "it's the shop's direct fault" - it could have been done better, but that's a tight space for a coolant hose. Could have been good at one point then something happened that pushed the hose into the turbine housing.

I would give the shop the opportunity to fix it or address the issue first before calling them out or anything. It could just be an act of God or honest mistake.

Dale

Could have done better is the shop's responsibility. Connecting hose to a turbo is unsat IMO

Hard to tell exactly from the photo on this display, oil feed, have they really used rubber hose? Personally like stainless fittings, or at least steel in close proximity to heat sources like this, that fitting will discolour at best - and likely go from T6 to T3 over time - that's why I hate oil drains that position big, near impossible to tighten AN nuts, next to the housing ready to go soft at an inopportune time.

Perspective might be off in this and previous pics, the feed doesn't seem particularly vertical, oil pressure will conquer the top, how is the drain?

I'd be very disappointed paying a "professional" that amount of money for this installation, if it hasn't been messed with.....assumed it was amateur hour from the past owner - eff me!!

In fairness, I did get what I paid for. I just didn't get what I asked for. I asked for anything to make the car run reliable and good. That included a recommendation (I accepted) of a new turbo manifold to replace an eBay one that came on the car. Also in fairness, I haven't found any other work where I felt it wasn't "what should have been done." This area just seems like a massive oversight, and one I would have easily been more than willing to pay to be done right.

I'm just gonna let them know and attempt to get the money I paid upfront for a tuning back. I've only put 60 miles on the car before this happened, so nowhere near the amount needed to tune. Unless a base map should cost $700, then I guess I'm just SOL. I'll look for another shop, time is my issue, not money.

I have no idea honestly. I blame my own ignorance/lack of knowledge. I wasn't an informed customer and didn't ask the right questions and/or be specific enough in my requirements.

Thanks all for the input. Trust me, I'd be the last person to trash a business and have no intent/desire to. I just want a running car. This project is going on over 3 years now, almost 2 years of that spent in shops, and it's just very tiring to think I was finally done and able to actually drive it. But, back to problem solving.

I could be in the minority on this, but IMO a reputable shop should provide recommendations in your interest (not theirs) and in certain situations not take your money if you don't agree with their recommendations. They are supposed to be the expert, not you, and because of that, should not be taking advantage of that fact. If they are not the expert, then they shouldn't be in business to begin with (IMO)