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oil pan 4 01-05-2017 03:39 PM

Fast warm up ideas: Oil to coolant heat exchanger
If you have a diesel truck you probably already have one. So :thumbup:
But gasoline trucks may be lacking or have an air to oil cooler. Which is what you don't want in the winter.
Yes most have a thermostat but everyone I have tested l allow at least some oil though.
Cars pretty much never have an oil cooler.
But the engine oil in a car can take roughly double the miles to warm up as compared to the coolant.
There was an old post on here about it but I can't seem to find it.
My big block Chevy had an oil to air cooler.
I am going to replace the air to oil cooler with an oil to water cooler. A stainless steel 40 plate 250psi rated heat exchanger.
I bought this heat exchanger to do a coolant to ATF heat exchanger but have since decided to go with a manual transmission.

Daox 01-05-2017 03:50 PM

Have you measured oil and coolant temp independently? I would think the engine would warm up the oil pretty quick if the coolant and block were already warmer.

oil pan 4 01-05-2017 04:33 PM

I don't have a temperature gauge but the oil pressure gauge will give a good indication of when the oil is warm.
On a freezing morning the coolant temperature on my fire bird will come up to operating range from a cold start after about 6 miles. The oil pressure doesn't drop into the normal pressure range until at least 10 miles.

oil pan 4 01-11-2017 11:23 AM

Another reason for the oil/coolant heat exchanger is about this time last year it was about 0F. I cranked up my 7.4L and it was knocking really bad. Before I fired it up I had ran the 5,500w coolant heater for the normal amount of time, then continued to run it for about 5 minutes. Because I thought it might be air in the lifters. After it didn't go away I figured it could be a rod bearing.
A few days later when it was 40F I went to fire it up to trouble shoot the knock and it was gone.
It was a collapsed lifter that was full of air.

Later when I tore the engine apart I found an air bleeding lifter oil galley plug had been clogged up with a chunk of oil sludge. So the air could only escape from the lifter oil galley when it was some what mild out.

So cold oil does you no favors.

Now I will be able to use the inherent power of my 5,500w coolant heater, and/or my two 600w engine block heaters to help warm the oil.

oil pan 4 01-11-2017 11:38 AM

2 Attachment(s)
This is what it looks like.
I think it will work because its slightly bigger than the heat exchanger that is in the radiator of a 6.5L diesel.
Both engines have oil pumps that pump a max free flow of around 20 to 25gpm.

It wasn't cheap, if I remember correctly this little deal was around $100.

Daox 01-11-2017 02:22 PM

How are you planning on plumbing this in? Are you planning on replacing your cooler with this heat exchanger?

oil pan 4 01-11-2017 03:52 PM

Yes replace the air to oil heat exchanger with coolant to oil.
I probably will not have an air to oil cooler at all on this engine.
On my diesel I added an air to oil cooler on a valve that I open in summer and close during the cooler months.

Daox 01-12-2017 01:40 PM

I was just trying to find some quantification on how much this may help fuel economy. Its obviously one of those YMMV scenarios. For me, I do a lot of short runs. My commute is 7 miles, to do a lot of shopping its less than that. Warm up is super important. For others, it may not be.

Anyway, I did find this article about oil viscosity and fuel economy. It basically says the difference between 10W30 and 15W40 is 1% in fuel economy. No specifics of how things were tested were shared. This is probably considering the engine is already warmed up. Therefore, fuel economy before warming would be even larger, thus warming is more important.

Research Shows Oil Viscosity Affects Fuel Economy - Article -

Daox 01-12-2017 01:45 PM

2 Attachment(s)
Found a bit more info. Here is a oil temp vs viscosity chart. If the lines are THAT close together at normal operating temperature (~90C), then at colder temps they are quite a bit more drastic.

Image from: Oil Viscosity Explained

Image from:

oil pan 4 01-12-2017 01:53 PM

Yeah I also drive about 6 or 7 miles to work each way.
I use 5w-40 just about year round.
For a summer road trip I will usually put in 15w-40 since it gets changed at the conclusion of the road trip or shortly after.

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