View Full Version : How big does the oil cooler really need to be?
My Jeep is only about 4800lbs, and the heaviest trailer I will ever pull is about 5K, and that won't be very often. Real estate is slim at the front of this thing - there isn't much room. I'm looking at a B&M plate style that has a 11x6 core as it will fit quite nicely beside the radiator. I can always add a small electric fan for additional air flow through the cooler.
Thoughts?
Go to www.bulkpart.com (http://www.bulkpart.com) and look for the TruCool brand. They are made by Long Mfg and you will find that they are the same supplier to GM for 6.5 trans coolers. I haven't looked close at B&M, but someone said the Long name was the company behind them as well. You should be able to find something for $70 or less.
They offer different configurations depending on what you want for engine oil or trans. I put a 29000 btu unit for an engine on my trans because I wanted the threaded fittings. It would have worked fine for the engine as well.
Yeah, they all appear to be the same unit. The question still remains - how big does the thing really need to be? I guess I'll start with what fits and see what happens.
I'm not worried about being too big - I'm worried about the cooler being too small. Is an 11x6 unit going to keep the oil cool enough?
tom.mcinerney
07-27-2005, 16:55
I can't really answer, but will offer this-
American cars rarely cool engine oil. VW/Mercedes, aircraft and marine usually do.
The cooling requirements for engines are directly related to their output HP. I don't know if all 6.5s came with coolers, or the 6.2Ls. I can measure the one on mine...
Earl's Performance Plumbing (division of Holley) had/has a selection of oil coolers of many different sizes/shapes. Might want to get their catalog. I'm planning to fit a cooler (used, from auto wrecking yard) out of a Mercedes SW ['1,2,3' 1980's] in my daily driver. Its dimensions are about 5"X24"(X2"thick). It's my understanding that the flat plate type of coolers are highly efficient in a high speed airflow , but useless in absence of good flow.
My guess is the peak load on the cooler would be 1)towing, and 2)idling in traffic after exiting the freeway. The OEM GM heatexchangers {radiator/condensor, trans&eng coolers} are not taxed when clean in stock configuration. What capacity do your other heat exchangers have compared with the stock OEM pickup/sub configuration?
Many autos are sold with marginal airflow thru their heat exchangers (cosmetics get preference). This can drastically impact duration and reliability. If the OVERALL airflow/cooling capacity is more than stock, a little shortchanging on one aspect should be OK. Some members here have raised the issue of cooling vents in the hood (like Hummer).The 'van' configuration is said to routinely 'fry' accessories and wire harnesses in those apps. I might consider using a marine (water-cooled) turbo on an application that had limited airflow(this just throws more heat into the exchangers, tho). Some Porches used to run the oil thru frame tubing around the whole body-pan, if IRC. Some members with MotorHome applications have speculated that inadequate underhood airflow has compromised their cooling efficacy.
So don't undercool-
Otherwise you may be threatening the longevity of this project many of us are following!
Point well taken. Bigger ones on the way. I have also decided to run a small electric fan over each cooler (trans and oil) as they will only have airflow when the vehicle is moving. I'm going to have them controlled by temp switches that will turn on the fans automatically at about 200* and off at 185*, plus I'll have manual override switches for them.
[grabs the sawzall and approaches the core support...]
Jeepsj,
Any particular size fan that you have found to sandwich between the grill and the tranny cooler & oil cooler.
I am wanting to do the same. I would like to go shopping at the junk yard...if you have already figured out which one fits best, I bet I am not the only one who would be interested.
I would probably set mine up like yours as well as triggered off of a relay for the AC...since the system isnt super effecient driving slowly around town or at idle.
Please post what size/model of fan you are using. Thanks
eracers999
07-28-2005, 18:09
The cooler i used really made a diff. Gained a 10 to 12 solid gain in oil psi.
Brent,
My setup is different since it is on my Jeep. I don't have nearly as much frontal area as a GM pickup, nor do I have much room for stacking things in front of the radiator.
So, in front of the radiator will be my A/C condensor and my intercooler and that barely leaves room for the grill.
Jeep has used this same core support since the beginning of time, and as a result it still has some nice big holes on either side of the radiator (used to be for some additional lights). I'm going to open those up and mount the oil cooler on one side and the trans cooler on the other. I have about 4" behind those holes to mount a fan. Behind that is another section of core support, but it is solid. I'll be opening some holes in there so that I can get flow through the coolers, and that may gain me extra space for fans. Deraele makes a 7" or 8" diameter fan that would fit perfectly in that space, and they are less than 3" thick. I hope to get the coolers this weekend so I can start cutting. I'll try to get some pics up soon - gotta show off the ceramic coated manifolds, down pipe, cross-over and turbo housing.
DA BIG ONE
07-31-2005, 22:05
Originally posted by JeepSJ:
Brent,So, in front of the radiator will be my A/C condensor and my intercooler and that barely leaves room for the grill. I removed my grill completely when I installed the B&M SuperCooler (largest). Using a dremel to cut out everything, put back trim ring and it looks great, but I have a WARN classic bumper, 12,000 hydro winch, and brush guard out front too.
Without the grill, and having extra large coolers in place of the grill it looks real rugged, kinda like a burb on steroids....IMHO
Your Jeep has down bars, a traditional Jeep feature, but you can change that look, or mod the grill by cutting out the bars and extending them outward somehow. If I remember right, that Jeep has a steel grill, so a mig/tig would go far to make it things fit, and pleasing to you.
Any pics of the coolers and the new grill?
It is posible to over cool oil.
If it doesn't reach at least 212 degrees it never has a chance to boil off moisture that builds up in the crankcase.
Ever look inside a valve cover and see white foam? An engine that never gets up to temp will cause this. That foam turns into sludge, and we all know that aint a good thing.
DA BIG ONE
08-01-2005, 19:24
Originally posted by Alf:
It is posible to over cool oil.
If it doesn't reach at least 212 degrees it never has a chance to boil off moisture that builds up in the crankcase.
Ever look inside a valve cover and see white foam? An engine that never gets up to temp will cause this. That foam turns into sludge, and we all know that aint a good thing. Yep, no moisture boil off is common problem on motorcycles too when used in the winter for short trips, been there done that.
Me thinks, a thermostat in oil cooling circuit is a must!
No down bars on my grill - you are thinking of the earlier style grills.
No pics yet. Coolers have been ordered and I'm waiting for them to be delivered. I'll get some pics of the overall project posted soon - gotta show off the freshly ceramic coated manifolds, crossover and turbo housing!
G. Gearloose
08-02-2005, 04:50
Ver nice...are they ceramic coated inside too, where it would be more effective?
Originally posted by DA BIG ONE:
Me thinks, a thermostat in oil cooling circuit is a must! I thought I had read somewhere that this was controlled by the bypass system in the block, and that oil only circulated to the cooler after it reaches a certain temp. If this is not the case, then a thermostat is a definite addition. Dang - just had my hands on one at Vetrans over the weekend. D'oh!!
Originally posted by G. Gearloose:
Ver nice...are they ceramic coated inside too, where it would be more effective? Most certainly. Nice beautiful satin black, good for 2000 degrees. I had the heat shield done in the shiny silver - needed to add a little bling.
tom.mcinerney
08-03-2005, 06:43
OEM 6.5 block has thermo control of the ports by the filter pad to&from the external cooler.
Earl's and PermaCool sell thermos for aftermarket installations in temperate regions. I think the thermos open flow at 180*F , and constantly bypass ca 10% oil even when cold to maintain airless flow (purge air in cooler and lines). It IS counterproductive to install an aftermarket cooler with no thermo in a cold climate. I assume that the 180*F set point was determined empirically. I doubt you'd experience sludge with the engine coolant at 180* or 195*, as long as the oil cooler had a thermo control. Sludge is a significant problem on brine-cooled boat engines where the coolant thermo is typically 145*F. For operations in cold winter temps a cardboard flap in front of the oil cooler is helpful at least for short runs.
If SJ were only running intermittently in a cool climate, and his engine coolant heatexchangers were full-OEM-sized, and the engine compartment had as much or better flow than stock configurations, then OK to cut back from the stock sizes on the oil cooler.
Oil coolers add to overall engine cooling, they cool at the heart of the engine , they delay the breakdown of lube oil. In any custom config you want normal, or extra CAPACITY because you haven't done the testing or engineering associated with production runs. That doesn't mean the capacity will always be required, it only helps decrease the chance of an overheat disaster , which only takes 5 minutes in unplanned circumstances.
Maybe I am just rewording several post here but wanted to clarify as to my understanding:
I am no expert for sure but I am pretty sure all that is built into the engine block is really a pressure relief for both the oil cooler and oil filter.
On initial start up with oil cooler cold, filter cold, and the oil thicker being cold the oil pump pressure is high and at least initially some maybe all (depending on temperature) oil blows past these pressure relief "bypasses" so it won't pop a leak somewhere. AND most importantly so as not to impede flow to vital lubrication areas. [I think this attributes to why cold engines have high oil pressure besides the oil being thicker]. Some oil will soon flow through cooler and filters as pressure becomes steady and the flow takes the path of least resistance. (Radiant heat from engine will also warm filter and cooler some too reducing viscous friction increasing flow to cooler and filter). In really cold places maybe the cooler never really gets warm enough to flow freeier than bypass which is not really a problem for the cooler but is for the filtration.
With more normal temps (guessing say at least 38 F ambient) I would say nothing really happens to regulate oil flow in a factory engine it all goes thru cooler and filter. Therefore: I would think a true thermostatically controlled flow to auxillary coolers not just the fan would be a good idea if they are sized for extreme high temps. And or maybe more so an oil temp guage would be in order for someone experimenting with oil cooler sizes.
Here is something I posted on another thread that relates and may be helpful:
Oil flow in a ~ 1997 6.5 diesel:
Oil out to cooler from the rear port (port closer to flywheel).
Oil return from cooler to front port.
Forgive this typing but from the GM manual:
A gear type oil pump pressurizes the oil with an enclosed pressure regulator. The oil pump uses bushings in the gears and a plate support the gear shafts. An oil pump drive operates the oil pump. The oil pump drive is driven by the camshaft.
The pump draws un-pressurized oil through a pickup screen in the oil pan. The pump pressurizes the oil distribution system. ... The oil flows from the pump to an oil cooler. The oil cooler bypass valve protects the oil cooler from high pressure during cold ambient temperature start up. The bypass valve is in the engine block oil galley to oil cooler passage. Next the oil flows from the cooler or the bypass valve to a full flow filter. The oil filter also has a bypass valve too. The oil filter bypass is located in the block above the filter. From the filter or bypass the oil flows to the mail oil galleries. An oil pressure sensor is located on the left main oil gallery. Oil flows from the main galleries the camshaft bearing bores. The channel in the camshaft bearing bores supplies oil to the camshaft bearings and to the main bearing oil galleries. Oil flows from the channel in the upper main bearing shells to the holes for the piston spray nozzles. The piston oil spray nozzles are pressed into the block. The oil flows from the upper main bearing shells to the connecting rod bearings. The oil then flows from the main oil gallery to the turbo. Oil from the turbo drains back to the crankcase through a gallery in the block.
Adlibbed and copied from 1997 C/K Truck Service Manual Book 1.
Published by North American Operations GM Corp. Warren MI. 48090
1996 info dated 5/29/96
The one I bought with my engine from Peninsular Engine is a Hayden. It is part #1240 and measures 6.5 x 18 x 1.5 and cools 11,000 - 16,000 BTUs/hr. This is a tube and fin design. Specs are in Hayden catalog at Hayden website http://www.haydenauto.com/assets/2005Haydencat.pdf . It will take a while to load. Go to Pg. 70 or 71.
moondoggie
08-04-2005, 09:18
Good Day!
[i]
tom.mcinerney
08-05-2005, 01:04
Hubert, thanks for the correction. After reading the relevant section in my manual i apparently equated 'pressure bypass' with 'thermal bypass' in my memory .
Last winter some 6.5L drivers in the north/central cold regions did report LOW oil pressure in very cold conditions....thought to result from the failure of thick cold oil to return-flow fast enough to the sump , starving the oil pump pickup.
I have heard cautions that cool oil can contribute to excess upper cylinder wear.
On any aftermarket cooler install i'd suggest a thermostat....i used one for an install here, where temps range a bit beyond +5*F to +95*F.
It would surprise me if there is really no thermal control on the oil cooler. Maybe just a symantic issue with the way the manual is written. Has anyone removed the cooler bypass valve and looked at it? Someone with a junk block sitting around?
Also, I suppose that even if it were just a pressure bypass, it could act as a temperature control of sorts. Thick oil isn't going to flow through the cooler very well, so if we equate cold oil with thick oil then when the oil is cold the cooler will bypass... Problem is that if that's the way it works, how do you get the hot oil to flow through the congealed cooler once it gets hot?
I still think it is a pressure bypass only. That mechanism is cheap, simple, and reliable. Just a little spring loaded pop off valve. Its to ensure good flow to the bearings etc regardless of oil temp. I agree I think it somewhat acts like a thermostat as cold oil does not flow as quickly or easily as warm oil but I don't think it is thermostatically controlled flow.
If the oil takes the bypass flow path initially it's more of a spring loaded popoff; the bypass path is still a restriction in the flow and oil will still push on the oil cooler path wanting to flow that direction too. I don't know but its must be pretty dang cold for the cooler and/or filter to plug up completely but cold it might be too much of a resriction for adequate flow for lubrication hence the pressure bypass. But once the oil is realtively warm its going to take the path of least resistance and may not popoff into the bypass path.
Side note: I think the filter bypass is something like 5 or 15 psi ?? to "pop it off" and flow around the filter (also think most filters have "popoff" bypasses built in too). I have never seen anything on the cooler bypass pressure. Or seen anything anywhere about a thermostat in a big three designed oil flow path for that matter.
As someone said above some big high performance aftermarket coolers have true thermostatically controlled flow. If not they may cool too much and oil can be too cool. I don't think the OE cooler is too big by design or any of about the same size but something significantly bigger or with a fan might cool too much.
If I am wrong, no problem; learn something new everyday. I am just trying to share my little bit of knowledge.
[ 08-05-2005, 03:28 PM: Message edited by: Hubert ]
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