> Third day I let
>it fully warm up before going to work and blocked the
>radiator with cardboard. NO problem that day. Called the
>dealer and told them, they said bring it in and they would
>leave it set outside and check it in the morning. That
>afternoon they called and said the tb was icing up, while it
>was this cold out just let it warm up longer. So yes they
>can freeze but it takes a temp extreme to do it. I know this
>was long but I hope it helps clear up some of the confusion.
>T. Roberts
>UFD Local 1147

That's some interesting real-world data. Thanx for the reply!

 

 

I have read the thread about taking the coolant lines off the TB with great interest. Some of the posts are now three years old, which is enough time to get long-term result. Have you noticed any long-term changes in the operation of the engine?
What if you just put a valve in the tubes before and after TB and shut off the flow. will that have any affect on the circulation of coolant through the engine?

Thanks.

 

I too would be interested in some updates here. How about just one valve in the inlet line? Would warm coolant still flow through the return line in the summer with the heat off?

 

It is the EGR spacer and it is suppose to only work when the engine is in open loop (not at operating temps, around 190). It is suppose to heat the incoming air so the engine can enter closed loop faster thereby reducing emissions and has nothing to do with ice. I am not sure what the ramifications are really, I know you dont get as good a mileage if you dont drive far between warm ups but other than that I dont know.

The reason you dont use carb cleaner down the throttle body is because it will coat the sensitive O2 and Mass air sensors with chemicals or coat them thereby rendering them either useless or decalibrate them. You can keep from doing this by making sure whatever solvent you use is Sensor Friendly and should state so on the can.

Good luck

Cheers

 

I did this a year or so ago with no ill effects. And the MAF sensor, on so-equipped Broncos, is upstream from the throttle body, so that's not the reason. There's supposed to be a coating in the throttle body that keeps carbon deposits from forming on it and carb cleaner will dissolve that coating.

 

There is no coating on the throttle body to keep carbon deposits on it. The MAF sensor is a simple wire wrapped around a piece of ceramic that is heated to a certain degree. The MAF computer senses how much voltage it takes to keep it that hot (increase in velocity = decrease in temp). If you shoot junk down the throttle body that isnt approved for the sensitive sensors you will foul them and they wont read the same. The O2 sensor is even more prone to being contaminated. To learn more about this click on the following link:
http://home.flash.net/~rfm2/massair.htm

hard to find info on the egr spacer.. still looking.. jury still out!!!

 

My point is, carb cleaner into the throttle body is about two feet downstream of the MAF in the intake plumbing, so you're not messing with the MAF at all. The only sensor between the throttle body and the combustion chambers is the air charge temperature sensor.

 

I don't mean to go off topic by going back on topic, but for the TB bypass, where did you find your joiner? I tried home depot, but all they had was copper, is it safe to use copper for the part? That is to say, is there any aluminum in the coolant flow path? (or any other metal that will react with copper?) Or where should I go to get a plastic piece? I know I can find them online, but I'd rather not pay shipping for a $2 part...

 

I put a TB by pass into my 5.0 1996 Bronco last year in Fall. As fo power, I did not notice anything. Same is true for gas mileage. Also, I did not have any issues regarding frozen TB. I live in Idaho where it gets pretty cold in Winter. We also had lots of snow with drifts sparying over the hood of the truck (fun). Still, no issues with frozen TB.

I think the coolant bypass does nat have a great affect because after driving for a while the entire engine compartment gets hot. The TB will experince heat soak and reach same temperature as ambient. As for issues due to the mods - I did not notice anything. Although I do not notice any affect, it was a fun project and cost only a few bucks.

Here is what I did:
- Installed a T-connector and valve (1/2' brass fitting from Home Depot, rubber hoses from Checker or Autozone) before TB (open = let coolant circulate through TB, close = coolant flows through bypass)
- Installed T-connector and valve after TB (open = accept coolant from TB and run back into engine, close = block coolant from bypass from running back into TB and run back to engine)
- Installed valve in bypass (open = run coolant through bypass, close = run coolant through TB)
Cost: about $2 per valve, about $0.30 for hose clamps, and about $5 for the 1/2 hose.
Recommendation:
- buy the valves and take them to where you buy the hose to assure fit
- buy two elbows. You will need them to avoid kinks in the hoses

To Engine<-----Valve<-----TB<------Valve<-----From Engine
| |
| |
<----------Valve<-----------

Valve Open Close Flow Open Close Flow
Before TB X Coolant X Coolant
After TB X flows X flows
In Bypass X through TB X through bypass

CAUTION: ALWAYS MAKE SURE THAT EITHER THE BYPASS OR THE PATH THROUGH TB IS OPEN!

- Ram air: Cut air-intake tip (was attached with a plastic rivet at the front, right under the Hood) and fitted it so it comes out the front next to radiator (right hand side of radiator if you stand in front of the truck). No issues with moisture despite snow and rain.
- wrapped entire air intake from tip over filter box to TB with heat reflecting tape.

Have fun with your project.

 

Use the brass one that you found at Home Depot.

 

FYI a_heldwein, you don't need the second valve. You say caution, don't run with them both closed, but it dosn't matter. if the water can't go through, it won't. It will just go back through the radiator instead. It would work the same way a heater valve does. They shut off flow to the heater with just one valve in the inlet line with no ill effects.

What I want to do is replace my intake manifold fitting with one that has a shutoff valve (readily available at any auto parts store). The one on there now has two nipples, one 5/8 for the heater hose and one 3/8 for the TB lines. I'll just get a 5/8 valve because I don't think you can get that kind with two ports. Then put a T in the heater line, run that to the TB, and leave the rest of the hose as is, with the return line from the TB going into the return line for the heater. Then in the summer I can shut off the valve at the intake so water won't go into the TB or to the heater, in the winter turn it back on and you have heat inside and heat to the TB, just in case.

 

Having a by-pass valve may not do much at all. The coolant in the line will transmit the heat anyways. The next question would be is the under the hood temp the same or different than the coolant temp supply line to the TB?

 

You promise the copper (they didn't have brass, unless it was mislabeled) won't react with anything else in the coolant? Coming from PC modding, I know that if you put an aluminum waterblock with a copper waterblock, you're glutton for punishment, as it will corrode (sp?) something nasty and is a right PITA to clean...

 

Yeah, they're copper. I've been using it for over a year with no problems. Your block and heads are cast. Your radiator and heater core are he only things that might have aluminum in them.