Coolant Hose Replacement Coming Up
#1
Recovering Miataholic
Thread Starter
Coolant Hose Replacement Coming Up
Slight coolant leak on our 98 K+ mile '94. Thought I might as well tear into it and replace all the hoses. Bought the 14-hose kit from Ray Crowe at Malloy, and as long as I'm at it, I intend to attack my high idle problem. Also bought gaskets, nuts, studs, etc. for a complete turbo/ exhaust/intake manifold removal. So when back from visiting grandkids on 6/23, I will start another fun FD job. If it looks to be worth it, I will post photos here.
#3
Original Gangster/Rotary!
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The high idle problem may be corrected simply by replacing your throttle cable.
You'll find that getting at the heater hoses on the pass side of the engine bay is fairly difficult with the stock twins still in the engine bay......every motor job that comes in we replace those hoses (along with all the coolant hoses) once the motor is out of the car.
You'll find that getting at the heater hoses on the pass side of the engine bay is fairly difficult with the stock twins still in the engine bay......every motor job that comes in we replace those hoses (along with all the coolant hoses) once the motor is out of the car.
#4
Recovering Miataholic
Thread Starter
The high idle problem may be corrected simply by replacing your throttle cable.
... getting at the heater hoses on the pass side of the engine bay is fairly difficult with the stock twins still in the engine bay...
#5
Recovering Miataholic
Thread Starter
Wow, this is a tough job. Tedious, mostly, but have had a few problems. I finally got the turbos "off," but the assembly won't go out the top or the bottom in the configuration the factory workshop manual shows. The factory air conditioning pipes block bringing it up and forward, and the oil return lines and turbo coolant lines interfere with dropping it down and moving it back. Tomorrow I will remove those front two actuators and see if it will come out then. Also, the manual procedure leaves out the turbo actuator heat shield removal. My biggest problem so far was one seized nut/stud of the 8 required to remove the turbos. Took me 2 days to get that sucker out... cold chisel, tungsten carbide-tipped drill bits, and two Vise-Grips to finally break it loose. Coolant hoses are scattered everywhere, and I'm going to replace all 14. To get to the LIM once the turbos are out of the bay I will still need to remove the UIM and associated stuff. Everything so far has been removal (except I did replace the lower radiator hose and the AST hoses). The input coolant hose to the turbo was sort of ballooned out, not like the replacement hose, but it wasn't leaking. Parts on the floor of the garage are labeled and placed in removal order, so if this job ever gets to the point where I put things back together, I should be able to reverse the order of removal.
So far I haven't seen any good reason for photos, but will later post anything that looks interesting.
So far I haven't seen any good reason for photos, but will later post anything that looks interesting.
#6
formerly chillin_rx7_guy
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I tried pulling the turbos off and I gave up since the downpipe was aftermarket and it would not come out. I just pulled the engine with the transmission and it's all gravy.
Good luck!
Good luck!
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#8
Recovering Miataholic
Thread Starter
OK, maybe half done now. The turbo came off forward and up after removing the front two actuators. Not in the instructions, but the disassembly section of the manual obviously assumes the engine is out of the car on a stand. I've R & R'd the LIM, whose gasket was broken in multiple places (fiber gasket). The new gasket is 3 layers of steel! LIM is back on, and now I'm fighting the solenoid rack installation. So far I've replaced all the coolant hoses at the firewall, throttle body coolant input hose, lower radiator hose, and two of the AST hoses. The other 8 hoses are off the car and will be replaced as I gradually build the engine compartment back up.
#9
formerly chillin_rx7_guy
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I took everything out including the downpipe. This pull was a lot harder than the last. Weird.
Good luck with yours. I'm sure you're like me and it feels good to replace all of those things at once while everything else is out.
Good luck with yours. I'm sure you're like me and it feels good to replace all of those things at once while everything else is out.
#10
Recovering Miataholic
Thread Starter
Decided to leave the exhaust manifold in place. There' s no leak apparent, and I don't see a point in R&R'ing it. I had enough trouble with a frozen nut/stud on the turbo, and don't care to go through that again. It cost me 2 days of pounding with a cold chisel and drilling with a carbide-tipped bit, both bought new. I completed 107 "removal" steps, and have now gone backward from that point through step 70. Next up is UIM re-installation; after that I am back on the passenger side to re-install the turbo, actuators, and downpipe. I'm replacing coolant hoses and the drive belts as I go.
#13
I just completed everything you are in the process of doing now. I took lots of breaks and spread the job out over a couple of weeks. Happy to say everything works great. Hope you have the same success. You will love the nice low steady idle, and the slight increase in power from not having a boost leak. Good Luck!
#15
Recovering Miataholic
Thread Starter
Finished today at 7 pm. Job took 11 days, pretty much 8-hour days straight through. Idle is now perfect (thanks to the new LIM gasket). No coolant leak so far (14 hoses replaced) but car has only been driven about 2 miles since finishing. Now, for some strange unrelated reason, the "seat belt" warning light is constantly flashing. Must be either an open switch or an open ground; will check the seat belt switch and ground #12 tomorrow.
There were roughly 110 removal steps in this job, and then the same steps were reversed to build it back up. This is as deep as I have ever been in this engine, particularly on the passenger side. It's amazing how many simple things are so hard to do... like sliding large hose clips on and off, getting screws re-started, etc. At least the objectives seem to be accomplished. The car is now at 99,000 miles... hopefully nothing further will break in the near future.
There were roughly 110 removal steps in this job, and then the same steps were reversed to build it back up. This is as deep as I have ever been in this engine, particularly on the passenger side. It's amazing how many simple things are so hard to do... like sliding large hose clips on and off, getting screws re-started, etc. At least the objectives seem to be accomplished. The car is now at 99,000 miles... hopefully nothing further will break in the near future.
#16
Recovering Miataholic
Thread Starter
Oops! Coolant leak is back... got the "Low Coolant" light after a 20 mile trip. Sure enough, the car started to overheat. We stopped & bought a gallon of Sparkletts drinking water from a gas station (would you believe they don't carry distilled or de-ionized water?) and added about 3 quarts. Drove it home, no low coolant light, but there is definitely a slow leak from something. At least I know it isn't from a hose. The undershield makes it impossible to locate the source of the leak, but I never saw any indication of coolant leak from the water pump when I had the engine apart, so it must be the radiator. Great...
The factory manual points to "CPU No. 2" as the culprit flashing the Seat Belt light. Also the "Security" light is now flashing when the car is unlocked. That is also a function of CPU #2.
So now it looks like we need a new radiator AND a new CPU #2. Has anyone else had a problem with this CPU?
The factory manual points to "CPU No. 2" as the culprit flashing the Seat Belt light. Also the "Security" light is now flashing when the car is unlocked. That is also a function of CPU #2.
So now it looks like we need a new radiator AND a new CPU #2. Has anyone else had a problem with this CPU?
#17
formerly chillin_rx7_guy
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Buy a fluorescent dye from the auto store where you can put it into your coolant and after running it five minutes and letting it sit for a bit, you can shine, I believe, a blacklight at your engine bay and find the fluorescent dye glowing.
Hopefully that'll help find your leak.
Hopefully that'll help find your leak.
#18
Recovering Miataholic
Thread Starter
chillin,
Thanks for your suggestion. During my hose replacement/LIM gasket replacement I searched for possible leak sources and found none. I believe the radiator is leaking, but cannot see it, of course. Even with the undershield off, the A/C condenser is in the way, and from the top there was nothing obvious that I could see through the fan area or at the ends. It's almost certainly the radiator, underneath somewhere(99 K miles on OEM rad.). A fluorescent dye doesn't help if you can't see the leak source when it's leaking.
Thanks for your suggestion. During my hose replacement/LIM gasket replacement I searched for possible leak sources and found none. I believe the radiator is leaking, but cannot see it, of course. Even with the undershield off, the A/C condenser is in the way, and from the top there was nothing obvious that I could see through the fan area or at the ends. It's almost certainly the radiator, underneath somewhere(99 K miles on OEM rad.). A fluorescent dye doesn't help if you can't see the leak source when it's leaking.
#19
Racecar - Formula 2000
chillin,
Thanks for your suggestion. During my hose replacement/LIM gasket replacement I searched for possible leak sources and found none. I believe the radiator is leaking, but cannot see it, of course. Even with the undershield off, the A/C condenser is in the way, and from the top there was nothing obvious that I could see through the fan area or at the ends. It's almost certainly the radiator, underneath somewhere(99 K miles on OEM rad.). A fluorescent dye doesn't help if you can't see the leak source when it's leaking.
Thanks for your suggestion. During my hose replacement/LIM gasket replacement I searched for possible leak sources and found none. I believe the radiator is leaking, but cannot see it, of course. Even with the undershield off, the A/C condenser is in the way, and from the top there was nothing obvious that I could see through the fan area or at the ends. It's almost certainly the radiator, underneath somewhere(99 K miles on OEM rad.). A fluorescent dye doesn't help if you can't see the leak source when it's leaking.
I assume you replaced the turbo-coolant hoses, which are also common leak points.
Dave
#24
formerly chillin_rx7_guy
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The good thing about the fluorescent dye is that you can see and trace where the leak is coming from, even in tight spaces because of it glowing. Even if you can't see the direct source, you can at least see where the coolant is hopefully pooling and you can work backwards on where the actual source might be.
Good luck and hopefully you can find it. I hate finding leaks but what's worse is if you have to re-tear down things to get to it.
Good luck and hopefully you can find it. I hate finding leaks but what's worse is if you have to re-tear down things to get to it.
#25
Recovering Miataholic
Thread Starter
I assume you replaced the turbo-coolant hoses, which are also common leak points.
Did you fill the radiator with water before installing in the car?
Is the coolant level still going down?
Also, is there any trace of white smoke coming out the exhaust?
Also weird... the fans never came on. Maybe because the coolant was below the temp sensor? I grounded "TFA" and the fans both ran, so the fuse and relay are OK.
Another weirdness... apparently due to reconnection of the battery with a slight spark, our seat belt warning light now continually flashes, and the "Security" light flashes all the time (should only when the car is locked). This points to a failure of CPU No. 2. I removed that box and am having a look at it.