Alfa Romeo Forum banner

Warming up a diesel engine

4K views 35 replies 21 participants last post by  Pud237 
#1 ·
A friend of mine told me that you didn't have to wait for diesel engines to warm up. Can't remember the exact explanation he gave, but as he's a farmer I wondered if this just applies to old diesel machinery and might no longer be true for modern turbo diesels.

Just curious if anyone knows?
 
#2 ·
Mine takes ages to warm up compared to a petrol car - in fact I read somewhere that because of this Alfa fit an electric heater to the JTD's to warm up the air when you switch your heater on until the engine has got up to temperature.

The user manual states that you should not leave the engine running to warm it up - just switch on & drive off
 
#4 ·
I treat mine the same way I have done all my cars... drive 10 miles before giving it some !! :)
 
#15 ·
But by then I've arrived at work, got changed, had a brew and completed the crossword.

I hope he's not just turning the key and firing it up. With diesels you need to turn the key, wait for the heater light to go out, start the engine. After that, until the engine is lubricated correctly and up to temperature it is not running at it's most efficeint.
 
#5 ·
I'd probably wait for temperature and oil pressure to be normal before thrashing it myself, but was just curious about this. I'd be inclined to think he's wrong unless anyone is sure you can just jump in and burn off.
 
#7 ·
You should warm up all types of engine before using full revs etc. Alfa recommend you wait 'til at least the needle is off the bottom of the gauge but I always wait til it's at normal operating temp ( a few miles or so).

Alfa used to be so keen on educating driver's that the Sud actually had red light which stayed on t'til operating temp was reached. Sud owners will remember it flickering when it was just getting to the cusp...Almost like a starting signal..........
 
#9 ·
Well you don't NEED to let it warm up, but you really should. You will be putting so much wear and tear on it by ragging it before its warm and the oil is hot.

However, if you turn the key and go for it performance will be 95% there, its only when they're really cold that the fuel is injected earlier to make sure it has enough time to burn.
 
#10 ·
My Merc was a diesel, and when you turned the key a coil light would come on, when that went off you were safe to start it. I then used to rag the pants off it from the off... it was only a lease.

With the Cup I always wait until the temperature guage has lifted before giving it anything above 3k-4k revs.
 
#16 ·
Before the advent of water cooled bearings in turbos, you were always advised to let the turbo coll down before switching the engine off, otherwise the oil would be burned off, which would not be good the next time you started the engine. Even though all modern turbos have water cooled bearings, letting it idle before switching it off is a good habbit to get into.
 
#12 ·
The turbo can still be spinning pretty hard after a blast and switching the engine of will stop the oil flow to the bearing !! Not Good !! :(

I always take it easy on the last mile or so and then sit for 30 seconds before switching off !! :)
 
#13 ·
He was probably referring to the glow plug heaters, which usually took 10 seconds on older engines, instant on new ones. Diesel does not warm up on tickover, petrol does. All modern cars should be driven gently to warm up, not driven hard until the oil warms up.
The old Field Marshall tractor was started with smoulldering paper stuffed in.
 
#14 ·
He was probably referring to the glow plug heaters,
He wasn't. I wish I could remember his explanation, because it sounded quite plausible at the time! I think it had something to do with lubrication. Obviously nobody else has heard of it, so it's most likely not to be true.
 
#21 ·
They have a 'Glow Plug' indicator light at start up though !! ;)
 
#24 ·
Common sense says keep your foot off the gas until thermostat has fully opened up.....keep it below 3000rpm. My 155 has travelled 180,000 reliable miles by being treated gently before being well spanked. I drive my jtd the same way. Leave your engine to idle for a minute or two before shut down.....this will save your turbo and greatly extend its life. In fact, its a good practice for ALL engines.:)
 
#30 ·
Common sense says keep your foot off the gas until thermostat has fully opened up.....
Ah, I think this is the nub of the logic for not leaving diesels to warm up at idle; 1) diesels don't really like running without load, and 2) diesels take so long to warm up at idle that you are actually prolonging the period that the engine is exposed to cold conditions (oil temperature, clearances etc.)
 
#31 ·
diesles need to warm up to achieve good combustion, that has always been the case, and it is why glow plugs are needed for a cold start. they also use engine oil, which gets thicker when it is cold, restricting circulation, leading to increased engine wear if driven hard before the oil has warmed up.

driving carefully from cold is fine on both diesel and petrol engines, but neither should be driven hard until they are warmed up.

this demonstrates why farmers should farm, and not give advice about engines.
 
#33 ·
this demonstrates why farmers should farm, and not give advice about engines.
Lol! To be fair, he'd got it from one of his mechanics. (Who is probably some old boy that learnt his trade in the 60s).

It's just struck me that I've never waited for a marine diesel to warm up before gunning it, nor know anyone who does. It doesn't make it right necessarily, but you often need full beans soon after starting it.

Either way, I wouldn't risk it on a modern diesel car.
 
#32 ·
My dealer told me something along the lines that these newer diesel don't really need the glowplugs and that they are there for extreme conditions, the glow plug computer thing in our stilo is broken and they actually recommended we don't bother fixing it if we don't mine the check fail bleep, not had a single problem starting all through winter etc.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top