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Coolant hoses on throttle body?

7K views 13 replies 6 participants last post by  DanComden 
#1 ·
I thought I'd done a thorough job last year completely changing the myriad coolant hoses on my '85 turbo...

While tracking down a high idle problem, I replaced the throttle body and discovered that coolant flows through that as well. And they are a pain to place and tighten properly, esp. when they are oil soaked and elderly.

I've looked around on a couple of online stores and can't find replacement throttle body coolant hoses. Apart from going to the dealer, does anyone have a source for these? Or can I just use generic lines?

Oh, and the high idle was traced to a bad O2 sensor...I think. Will know more in a couple of hours when I swap it out.
 
#4 ·
I can't see that any of the usual online parts sites have these hoses. They're not listed on the diagram at eeuroparts nor can I find them in the Bentley. Or perhaps I'm being thick.

There are four hoses into the side of the throttle body facing the engine. The two closest to the firewall are the ones in question. The lower one goes down to the air intake joint after the AMM (and mine is leaking coolant now). The upper one dives under the fuel rail. The two forward of that go to the AIC and turbocharger and cleary carry air.

The one that is leaking appears to be larger on the throttle body side than the side going into the air intake. At least, when I tried to put a spare piece of hose I had lying around, I could get it on the air intake side, but not on the throttle body side, as it wasn't quite wide enough. I can probably buy a reducer and make it work, but it'd be nice to have the correct hose, if it can be located without going through a dealer.

I'm guessing these lines are there to keep the throttle body from freezing?

I'm pretty sure the upper line I can replace with a standard hose, but the one that's leaking seems custom made. Like I said, perhaps I'm being obtuse, and not for the first time.
 
#5 ·
Checked on EPC but can't find the hoses. They must be there somewhere but not on the coolant hoses page and not on the throttle-body page. I know which hoses your talking about; your not imagining it! :lol:

You could just connect the hoses directly to eachother so they don't pass through the throttle-body. It's actually a power-mod. On the basis that warm coolant passing through the throttle body heats the air. Some people join them up to by-pass the TB. I have also heard that the system is there to stop the throttle-plate freezing shut in winter. Here in surban London I wouldn't have a problem disconnecting it as I think it's hardly likely it would freeze shut... you need really cold weather for that kind of problem.
 
#6 ·
Thanks for verifying my sanity :)

I broke down and called the local Saab dealer. They had to look around a bit and call back, but did locate the hoses. The part numbers are:
upper throttle body coolant hose: 7482953
lower throttle body coolant hose: 7519531

They have 'em in stock so I guess I will have to bite the bullet and make a dreaded dealer visit.

I considered bypassing the throttle body, however I do occasionally take the car to some chilly climates, as in below zero temps, once or twice a year. My hope is to get this car ready for the winter Alcan 5000 rally in 2008; when I competed in 2004, we saw -30 (F) a few times. So I think I will keep the stock setup and look for performance gains in other areas.

Now to attack that stubborn O2 sensor...
 
#7 · (Edited)
my coolant hoses there are leaking as well (very slowly but nearly ruined a starter motor).
ok here's my idea.

Wouldn't i be able to just route one hose so that the coolant doesn't go through the TB?
That would give me a cooler intake air temp, and less places to leak from. I live in Santa Barbara and Los Angeles CA where it NEVER freezes (if i go into the mtns i'd change the hose obviously).

IIRC there are coolant ports at the intake manifold flange, does the coolant go from the TB->manifold or is it separate?
 
#8 ·
I'd leave it to folks a lot smarter than me about upgrades to answer the question about better performance by removing coolant from the throttle body. It makes sense to me that keeping things colder in that location could improve performance. But how much? I dunno.

In my opinion, keeping the stock setup here makes sense if you even think there's a chance the car will be taken into subfreezing weather. Doing your proposed switch just for mountain driving would be an additional prep item for any trip, something to not forget, and it's not exactly a quick swap. I can get the throttle body R&R'ed pretty quickly by now, but fussing with additional coolant lines would be a hassle. The dealer price for the two hoses was ~$40. A bitter pill to swallow for two teeny rubber lines but them's the breaks.

O2 sensor swap update: I could not remove it in situ. Had to unbolt the elbow and put it into a vise and get a big ole wrench on the sensor to get it free. This was after two evenings of applying heat, PB Blaster, and percussive persuasion. I replaced with a Ford sensor that required soldering the wires. Will get things reassembled this evening and see if that has solved the high idle ...
 
#9 · (Edited)
I believe the brass fittings on the TB leak, which would be a PITA to fix, and i havent been to the mountains in about 8 years, and i don't have any plans of ever taking my car up there -- seriously; that was the "in the ultra-nearly-impossible-rare-event" case example, and even then it would be in the summer when its HOT.

Does anyone know where those hoses go to? do they just go into then outof the TB and nothing else? that's sure what it seems like.

EDIT
PS one of the lower bolts on the TB absolutely WILL NOT come off. vice grips, the right size box wrench (tried in the reverse order of course). it just seized and stripped. i hope i never have to take that SOB off. there's little room for a saw or drill in there, so i guess i'd have to go the cutting-torch route.

does the TB gasket have a water jacket in it? if not, then it'd be safe to assume that the coolant stays in the TB (from those two hoses).
 
#10 ·
Bypass?

I have, on another car, done a throttle body bypass. The coolant lines provide heat to keep the cool air from flogging the motor, right? I bypassed the crooked little guy and straight piped the whole mess and put caps on the throttle body. Just a thought, cooler air means more efficient fuel burning?

What is the forum's thought on bypass?
 
#12 · (Edited)
I just had this all apart a few days ago, so I thought I'd pull out my old parts and take some pics.

Here's the side view of the throttle body. You can see that the nipples for air are brass colored and the coolant ones are not. Also, the coolant nipples are corroded -- someone didn't use high quality coolant, did they? This plate was off of the replacement body I got from ebay -- I swapped it out with my original because it was ugly, though the rest of it seems to function just fine.




You can see the plate with the coolant nipples now that the throttle position switch is removed:
 
#13 ·
And now that the plate is removed, you can see the channel where the coolant passes through the throttle body. That's all there is to it.


And here's a close-up of the cover. It uses the same kind of rubber seal that mates the throttle body to the intake. This one is pretty ugly looking -- I cleaned up mine before installing it.


So if you have a coolant leak, I doubt it's the nipple, since they're all part of the cast cover. It's more likely to be either in the hose/clamp or in the seal between the cover and the rest of the throttle body.
 
#14 ·
PianoDavid said:
I...
PS one of the lower bolts on the TB absolutely WILL NOT come off. vice grips, the right size box wrench (tried in the reverse order of course). it just seized and stripped. i hope i never have to take that SOB off. there's little room for a saw or drill in there, so i guess i'd have to go the cutting-torch route.

does the TB gasket have a water jacket in it? if not, then it'd be safe to assume that the coolant stays in the TB (from those two hoses).
Ouch. That's a tough bolt to access. I found removing the air filter box gave me a little more room to fiddle around, if you haven't already gone that route. A day or two soaking in PB Blaster or the equivalent might help if the bolt head isn't completely shot. Hammering on a smaller wrench would be hard to do at that angle. Maybe one of those short hacksaws?

You can see from my pics what the little TB coolant channel looks like. It doesn't go anywhere near the o-ring at the intake manifold. I don't know what the proper name for that would be. Sounds like bypassing that system would be a good solution for you.
 
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