I've had a coolant leak for a few days now, haven't found it yet, but last night for the first time I realized I'm getting hissing/sizzling from under the TB or UIM. Can't find any water dripping down, so I can't exactly position the leak.



Now, if that damned line coming out of the bottom of the TB is leaking, where would the water land? On hot engine parts? Can I get to it and REMOVE it by pulling the TB alone, or do I need to pull the whole UIM assembly off?



This probably came about as a result of me being tricky and working on my 6 port sleeves without properly pulling the UIM off...I just pried it up as far as possible, and wiggled the LIM off. Probably cracked the line in that process...



So, is there another coolant line in the region hidden from view, or is there a really good chance that it is the culprit?



Finally, can I remove the BAC/TB coolant lines *without* doing the TB mod?

That's the only coolant line that runs under the UIM to the housing.. You may be able to bypass or cap it without removing the UIM but it will be a bitch. No, you don't have to do the TB mod, you can leave the thermowax sub assembly attached to the TB and just run a line direct from the back of the water pump housing to the nipple under the UIM bypassing the BAC. But if you have it all off, you might as well mod it.

I simply don't want to do the TB mod because I need to get this running first. The mod is in the future though...

This came at a bad time for me, I just don't have the actual hours to work on it until next weekend, unless I sit in the rain and work by troublelight tonight https://www.nopistons.com/forums/pub...IR#>/angry.png



Thanks for the help. I will probably remove the complete BAC/TB line, and let the car overrev at idle until next weekend (most of my driving is highway anyways, it won't make much difference, and the ricers will all think I'm trying to drag them at the lights https://www.nopistons.com/forums/pub...IR )

try pressurizing the coolant system then looking for leaks with the throttle body unbolted but not completely removed. that should find it

I'm 90% sure it's that line or connection. I get a hissing sound from the general area under the UIM, and the sizzle of water dripping on hot engine. I know I'm losing coolant, I can't find any drips, can't see any leaks.



So, I'm going to climb in today...but...

Could I just plug the line going into the BAC, and try to plug/tape/glue the line coming out of the TB, as a temp mod until I can tear into it next weekend?

sure you could try it.. not sure how it'd hold up. I thought someone capped theirs right at the BAC too but I haven't see "coolant caps" really.. that would work though.

Coolant caps=whatever I can scrounge/make/carve that'll fit in there https://www.nopistons.com/forums/pub...#>/biggrin.png



I think my main question is which way does the coolant flow through that system, is it waterpump->BAC->TB->waterpump, or the other way around. If I can just cap the inlet side (which is easy to get to if it flows that way), then I have a 10 minutes fix ahead of me. If it flows the other way, then I'll have to find a way to access the hose between the water pump and the TB (hopefully near the WP) and cap it there. That's an hour fix. If I need to pull the UIM, then it's a sitting in the desert outside sweating like a stuck pig until I bust all of my knuckles open and break something fix https://www.nopistons.com/forums/pub...DIR#>/ohmy.png

If its not leaking very bad just keep a close eye on the water level and order new hoses through mazdatrix or something. Depending on where you live, they will take a few days to get to you, by that time maybe you will be ready to pull the uim off.

check underneath your alternator. the gasket there went bad on the water pump housing to the block, and it produced a loud hissing sound.

No, I'm pretty sure it's the line under the UIM, I can hear the hissing loudest from the firewall side, but it is obviously under there. I didn't get to work on it (went home Friday, had a few too many instead of standing in the rain to work on it https://www.nopistons.com/forums/pub... ). I'll try this week, or the weekend for sure. It's leaking too much (I drive 55 miles each way highway to work, I have to stop 3 times and top it off, about 2.5 quarts each way). Hell, I might just grab the TB from the boneyard, do the mod in comfort, then swap the modded TB in at the same time I remove the line...



Or I'll just burn the whole thing https://www.nopistons.com/forums/pub...IR#>/angry.png



While I'm asking tech, I have a leak in the soft line for the clutch (the short one near the firewall). Is this the same as a brake line (fittings, size)? I'd rather just grab a cheap brake line and put it there, Vs an expensive stealership part, or wait for a semi-expensive Mazdatrix part...