1980 240D running on the HOT Side... - Page 2 - PeachParts Mercedes-Benz Forum

Brian Carlton · #16 08-10-2006, 08:11 PM

Quote:

Originally Posted by a_merc

Hi Ed,
I also realized that the wastegate is controled by vacuum on my 83 300D turbo................... It looks as if wastegate operation is controled by vacuum and if so, also controled by engine temp.

So my theory, the wastegate is interupted by this sensor/switch in the t stat housing while the engine is cool. With proper e temp, the vacuum switch on the t stat housing opens allowing vacuum to the wastegate to operate. If the wastegate stays closed all the time your EGT's would continue to increase because your compression from your turbo is not controled properly.

Your wastegate is not controlled by vacuum........it's controlled by intake manifold pressure.

Your wastegate has no control from any sensor or switch in the thermostat housing. That switch is strictly for your EGR and you can disconnect the lines to and from the switch and toss 'em.

Furthermore, if your engine is running at 115°C., you had better seriously consider parking it and finding the problem. You're in danger of cracking the head up at those temperatures. Change the thermostat and be sure that it's not the culprit. Then pull the radiator and thorougly clean the external fins with condenser cleaner and/or compressed air and/or a pressure washer. If done rigorously for two hours, you might get the radiator back to a decent operating condition. If not, you need to replace the radiator.

Don't compromise a $1000 head to save $250. on a radiator.

a_merc · #17 08-10-2006, 08:58 PM

Quote:

Originally Posted by Brian Carlton

Your wastegate is not controlled by vacuum........it's controlled by intake manifold pressure.

Your wastegate has no control from any sensor or switch in the thermostat housing. That switch is strictly for your EGR and you can disconnect the lines to and from the switch and toss 'em.

Furthermore, if your engine is running at 115°C., you had better seriously consider parking it and finding the problem. You're in danger of cracking the head up at those temperatures. Change the thermostat and be sure that it's not the culprit. Then pull the radiator and thorougly clean the external fins with condenser cleaner and/or compressed air and/or a pressure washer. If done rigorously for two hours, you might get the radiator back to a decent operating condition. If not, you need to replace the radiator.

Don't compromise a $1000 head to save $250. on a radiator.

Wow, shake the tree and see what falls out.

I am surely glad you posted this.

However, since adjusting the vacuum lines as I posted, I have had a reduction in E temp to the 100c mark at a ambient temp of 95F, on the highway, and generally 90c for in town stuff with about the same ambient.

Is this a safe operating range?

Also I have no aux cooling fan. It was removed because the bearing was fried. I am looking into purchasing an aftermarket 1250cfm fan to increase effeciency.

I also have no fan shroud, this might be a small problem when it's just the forced air doing the cooling instead of the mechanical fan.

I believe the radiator to be new. As it shows no wear and is very clean.

If I remove the vac lines to the EGR, where is the best place to terminate the lines?

and wont that effect to overall preformance of the vacuum system?

Brian Carlton · #18 08-10-2006, 09:25 PM

Quote:

Originally Posted by a_merc

However, since adjusting the vacuum lines as I posted, I have had a reduction in E temp to the 100c mark at a ambient temp of 95F, on the highway, and generally 90c for in town stuff with about the same ambient.

Is this a safe operating range?

If I remove the vac lines to the EGR, where is the best place to terminate the lines?

and wont that effect to overall preformance of the vacuum system?

I'm really not sure of what you did, but, I can assure you that no adjustment of any vacuum lines will allow the engine to run cooler. If you replaced the wastegate hose, you may have fixed a problem with too much boost, but the engine is not controlled by vacuum in any way.

100°C. is fine. No further concerns at that temperature. The SD will run 100°C. in traffic after coming down from freeway speed. It's not bothered by it.

You'll see three lines running to the black box on the valve cover. One line goes to the coolant switch in the thermostat housing. Pull this line off and toss it away.

A second line goes to a "T" near the brake booster. Pull this line off and toss it away. But, you have an open port in the T.

Remove the T and toss it away. Connect the two open pieces of tubing with a short piece of 4mm vacuum hose.

A third line also goes to a different "T" also near the brake booster. Do the same thing........toss out the line.........toss out the T.........and connect the two pieces of tubing with a short piece of hose.

Done.

No, the overall performance of the vacuum system is unaffected.......provided that the 3-2 valves on the valve cover were not leaking. If they were, then you'll have higher transmission vacuum and you'll notice a softer shift.......with a possible flare. This can be adjusted........if it occurs.

a_merc · #19 08-10-2006, 11:15 PM

Wow we have really hi-jacked this one.

The EGR is abviously not important?

Just the transmission, locks, and close up all vacuum lines south (meaning toward you as you face the car) of the manifold?

wow sounds like the fun I had with my 79' jeep cherokee after it didnt need emission inspection any longer. I still have vacuum hoses in my garage from that event.

Thanks!!

sailor15015 · #20 08-10-2006, 11:20 PM

Quote:

Originally Posted by 85chedeng300D

I don't think fixing a bad ground will fix an overheating engine. It might correct the intermittent or low water temp. gauge reading but not the overheating itself, and IMHO, a bad ground will show a lower temp gauge reading and not a high reading. Try to disconnect the wire on the water temp. sender, which means no power, therefore the reading will be lower or zero degrees. So, a bad ground will be a low power, or high resistance which will obviously read low.

That's why the word "overheating" had the "'s. It wasn't really overheating, and yes, a bad grounding issue will cause the gauge to read high and, in my case, it fluttered a bit. I had this same problem. I let my car idle with the gauge twittering at about 110 degrees C. I got under the hood and bolted an extra ground strap from where the turbo oil supply tube bolts onto the air filter housing to where the battery grounds out to the body and, ta-da!, the gauge settled right at 82 degrees C. A bad ground will indeed cause a high temp reading.

Brian Carlton · #21 08-10-2006, 11:49 PM

Quote:

Originally Posted by a_merc

Just the transmission, locks, and close up all vacuum lines south (meaning toward you as you face the car) of the manifold?

Follow my post, above, explicitly. There are vacuum lines to and from the vacuum control valve and the IP shutoff valve that cannot be removed.

Do not go off and remove every hose in sight or you'll get the system FUBAR'ed. If you don't understand exactly what I explained, above, do not touch the system.

a_merc · #22 08-11-2006, 12:35 AM

Quote:

Originally Posted by Brian Carlton

Follow my post, above, explicitly. There are vacuum lines to and from the vacuum control valve and the IP shutoff valve that cannot be removed.

Do not go off and remove every hose in sight or you'll get the system FUBAR'ed. If you don't understand exactly what I explained, above, do not touch the system.

i do understand what you are saying. Before I touch it I promise I will go over your message 10x's.

Thanks for the help.