Should I let my 3.0 warm up? - Page 2 - Jeep Garage - Jeep Forum

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  #13  
Old 04-08-2015, 10:42 PM
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Re: Should I let my 3.0 warm up?

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Originally Posted by C175 View Post
I let mine warm up, 5 to 10 minutes from cold start. just hit the remote, many reasons behind this, both engine and transmission related. I am an engineer for an OE Diesel engine mfg.


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Hey C175,
Could you please elaborate on the "many reasons" that are "both engine and transmission related?" I'd like to know why the 3.0 VM engine and ZF 8 speed transmission need 5 or 10 minutes, from your perspective as an OE Diesel Engineer

Wiley75

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  #14  
Old 04-08-2015, 11:34 PM
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Re: Should I let my 3.0 warm up?

When the engine is warming up the transmission is coming up to temperature. With a cold transmission you can have slippage, seals leak etc. Engine wise I'd rather see the engine warm up no load to 100*F before driving, 160*F before full load. The pistons swell up with heat as do the rings to fit the bores. Running a cold engine the pistons are slapping around and getting additional blowby with the ring gaps wide open, without any warm up.


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  #15  
Old 04-09-2015, 06:14 AM
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Re: Should I let my 3.0 warm up?

Mine warms up whilst I back it out of the garage then it is game on....


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Old 04-09-2015, 07:16 AM
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Re: Should I let my 3.0 warm up?

Quote:
Originally Posted by C175 View Post
When the engine is warming up the transmission is coming up to temperature. With a cold transmission you can have slippage, seals leak etc. Engine wise I'd rather see the engine warm up no load to 100*F before driving, 160*F before full load. The pistons swell up with heat as do the rings to fit the bores. Running a cold engine the pistons are slapping around and getting additional blowby with the ring gaps wide open, without any warm up.


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It takes forever for this engine/transmission to reach operating temp. I usually let it warm for 2 min in the driveway and go, per the manual. I won't see 160+ until 10-15 min, and operating temp of slightly over 200 around 20 min, and that's while driving. The transmission however takes an hour. It usually settles in the 190s. My daily commute is 30 min so it's never getting there. The engine will warm the transmission, but I doubt to any reasonable temp for a while, and then you're redirected to the threads about excessive idling.
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Old 04-09-2015, 07:36 AM
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Re: Should I let my 3.0 warm up?

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Originally Posted by Timo13 View Post
It takes forever for this engine/transmission to reach operating temp. I usually let it warm for 2 min in the driveway and go, per the manual.
I had mine this morning over 100*F oil temp less than 5 minutes idle, this engine warms up quicker than most diesels.
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  #18  
Old 04-09-2015, 03:16 PM
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Re: Should I let my 3.0 warm up?

I should have clarified that my emphasis was on the transmission taking forever. Just took a 43 min trip engine start to stop, with two idle breaks while I ran in two stores. Took readings every min but here's the breakdown:

Before starting
Outside temp 40
Garage temp 43
Oil 42
Trans 44

Min/oil/trans
Start+
1/48/48
2/59/51
3/69/55
Left garage after 3 min idle
5/102/68
10/161/86
15/192/102
idle break min 15-19
19/194/107
20/195/109
21/197/113
Idle 21-25
25/195/118
30/201/136
35/201/149
40/199/159
Parked
41/197/161
42/197/163
43/197/163

Noticing the idle times the trans temp still rises meaning its being warmed by the engine. Still had 30 or so degrees to go after 43 min.
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Old 04-09-2015, 10:47 PM
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Re: Should I let my 3.0 warm up?

Quote:
Originally Posted by C175 View Post
When the engine is warming up the transmission is coming up to temperature. With a cold transmission you can have slippage, seals leak etc. Engine wise I'd rather see the engine warm up no load to 100*F before driving, 160*F before full load. The pistons swell up with heat as do the rings to fit the bores. Running a cold engine the pistons are slapping around and getting additional blowby with the ring gaps wide open, without any warm up.


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Hmm. I guess I was looking for something a bit more specific.

You are supposedly an engineer for an OE Engine Mfg. I presume you mean Caterpillar, since your name on this forum is "C175" and Caterpillar has an engine called a C175.

I took the liberty to view the C175-16 locomotive engine (86 liter V16) Operation and Maintenance Manual today. It recommends "2-3 minutes" of engine warm up. Then operate at low rpm and low loads until it is showing heat on the jacket water temp gauge.

I also checked the Operation and Maintenance Manuals for Caterpillar's smaller 4.4 liter engine, 7 liter engine, 27 liter engine, and 69 liter engine. In no cases was cold idle for 5-10 minutes recommended.

In fact, extended idle is specifically not recommended, especially when the engine is very cold. When cold, partially burned fuel mixes with water from atmosphere and forms a sticky goo that sticks to the exhaust valve stems. The longer the engine is operated cold, the more goo collects on the valves. Also the ring lands and exhaust manifolds, exhaust turbine. This is why Caterpillar recommends idle for 2 or 3 minutes, then gently putting the engine to work, thereby vastly speeding up the warm-up time..... thereby minimizing the "goo"

Our 3.0 engines are similar no doubt. But even worse. Our DPFs cannot passively regen at cold idle.

So, I must respectfully disagree. My opinion, is that when it's very cold outside, the best thing you can do is let your 3.0 idle for a few minutes only, then gently drive it until it is warmed up. Then stomp on it as much as you want.

I'll admit that sometimes I let mine idle when cold for more than 3 minutes, but solely because I want the interior to be warmer when I load my 5 month old kid into it. I fully know that I'm doing my engine no favors by letting it sit and idle when cold.
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Old 04-11-2015, 01:44 PM
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Should I let my 3.0 warm up?

Dude I can tell you the only reason you don't want to idle for a long time is carbon deposit buildup, but in actuality any operation outside of recommended temperature will cause more wear, and this wear is proportional to the amount of load the engine experiences. Again like I said before if you absolutely want to make the engine itself last the absolute longest, ie cams, valves, rings, bearing, wall roundness, etc you should operate your car at standard operating temp only and use fuel injector cleaner to combat any carbon buildup. Can you idle for 3 minutes and go? Yes. How much more wear will this cause vs idling till operating temp? Very low. Will you notice in a leak down test after 100k? Yes. Will it still be in within specs? Yes. It's your car only you know how long you want to keep it for and if you engine is still 100% and the rest of your car is falling apart.....

I idle for 3-5 minutes before driving, because I don't plan to keep the truck forever and also because I'm cheap and don't want to burn fuel. As long as you don't load the engine much before fully warmed up you will be fine, that is the worst thing you can do.


Hope this helps.
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Old 05-01-2015, 10:26 AM
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Re: Should I let my 3.0 warm up?

Quote:
Originally Posted by Wiley75 View Post
I took the liberty to view the C175-16 locomotive engine (86 liter V16) Operation and Maintenance Manual today. It recommends "2-3 minutes" of engine warm up. Then operate at low rpm and low loads until it is showing heat on the jacket water temp gauge.
First thing, revert back to the topic of the original post. This regarding engine starting in cold temperatures and granted you referenced a manual SEBU9204, but left out following sentence after it was stated "operate engine low idle two to three minutes". Followed by "allow the jacket water temperature begin to rise before increasing the engine rpm to rated rpm". Also left out the following from page 33.

NOTE: More warm up time maybe necessary when ambient temperature is below -18*C (0*F).

Page 32 it explains allowing the engine to idle for 10 minutes during an inspection, fyi.
Quote:
Originally Posted by Wiley75 View Post
In fact, extended idle is specifically not recommended, especially when the engine is very cold.
Its interesting you bring up locomotive because, loco's are idled for hours in many cases. More recently systems have been developed to cut down locomotive idle time to 30 minutes ("AESS").

Quote:
Originally Posted by Wiley75 View Post
I also checked the Operation and Maintenance Manuals for Caterpillar's smaller 4.4 liter engine, 7 liter engine, 27 liter engine, and 69 liter engine.
By comparison, the way Tier 4 has been handled with air compressors and generators, they have a pre alarm for DPF full, and it requires a manual forced regen with laptop connected. Those applications are run for hours at minimal load, they can't go to full load like a road vehicle.

Quote:
Originally Posted by Wiley75 View Post
When cold, partially burned fuel mixes with water from atmosphere and forms a sticky goo that sticks to the exhaust valve stems. The longer the engine is operated cold, the more goo collects on the valves. Also the ring lands and exhaust manifolds, exhaust turbine. This is why Caterpillar recommends idle for 2 or 3 minutes, then gently putting the engine to work, thereby vastly speeding up the warm-up time..... thereby minimizing the "goo"
When you burn a gallon of diesel you end up with a gallon of water, its the chemical equation, its more noticeable when its cold, when the exhaust outlet temperature is below the dew point, water vapor in the exhaust will condensate. The goo you call it, more often called wetstacking, slobbering etc. Its a mix of water, carbon and oil. However our engines can go to full load, burn off the carbon, so its not as common of an issue for us. Carbon will build up no matter how its driven.

Quote:
Originally Posted by Wiley75 View Post
Our 3.0 engines are similar no doubt. But even worse. Our DPFs cannot passively regen at cold idle.
Correct, but unless you idle for 8 hours + you shouldn't be near the point of needing a regen.

This whole thread is about cold starting, lets specify sub 0*F starting. Under those conditions I would be looking for 5-10 minutes of no load warm up from sub 0*F ambient temperature. The engine has areas of expansion for sealing and loading and when not warmed up sufficiently will prematurely wear (ie piston skirts).
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Old 05-06-2015, 11:22 PM
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Re: Should I let my 3.0 warm up?

You've confirmed all of the points I made. Sounds like we are in agreement with each other and most of the other folks that posted on this thread.
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