external oil coolers?

[urtheiz]

Hooking up an external oil cooler in my bus and i have a question. i have a dog house fan housing, jus' wantin' to know when i hook up the oil bypass and remove stock oil cooler, do i need to cover up the backside of the fan housing where the oil cooler used to be? thanks

[ruckman101]

I think I would swap out the tin for a non-doghouse style shroud, but yes, at least block off the hole.


neal

[urtheiz]

Thanx Neal, thats what i was thinking (otherwise i'd loose all the air). i do have one of those 36-40hp shrouds. think i'll use that. this wkends project. hope things are good

[dtrumbo]

Why would you remove the stock cooler? More is better, no? My wife's '70 had an external cooler (since removed) but the stock cooler was still there doin' it's thang jus' fine. It still is.

[Amskeptic]

Why would you remove the stock cooler? More is better, no? My wife's '70 had an external cooler (since removed) but the stock cooler was still there doin' it's thang jus' fine. It still is.

Personally? I'd keep the dog house cooler and dispense with any external annoyances with their dozen new failure points.
Colin

[urtheiz]

i'm putting in the external cooler cuz' my enginges been running hot for awhile. replaced the old dghse oil cooler (once it got hot on just a 15 mile fwy drive pulled over an' some smoke was coming out (pulled over right away, leak was from where oil cooler was, which is why i replaced it) cyl pressure is low 100's. timing is set at 7btc, have a pertronic ignition. Valves are at .006 (which is the 1st thing i check when it overheats) pressure and controll valves have been recently replaced (both were sticking) and it still running hot!!! can't figure it out, which is why i'm going to the external cooler,, one of those big coolers (empi/mesa) with auto-temp switch for the fan. already got it mounted on the left side engine compartment (oppisite the battery). also while i have the engine out of the car i'm gonna put in a new oil pump(maybe thats the problem), which will be a 1st for me. oil pressure at engine start up is 60+ and as the heat goes up, of course the pressure goes slowly down, when the temp gets to 'round 200 (sez the gauge), the pressure seems to drop alot. 20lbs or so driving and 5 to zero at a stop lite or going slow (pullover, open the engine hood, take the oil cap off). Thing is this sometime the overheating dosen't happen............

[Hippie]

Does smoke come out of the filler hole when it's hot? 200 degrees F isn't really hot for oil.

[SlowLane]

Your temp and pressure niumbers don't seem all that much out of the ordinary. Maybe your running pressure seems a bit low. Are you using 20w50 oil? As Hippie said, 200F is not that hot for oil. In fact, it's too low to boil off any condensation in the engine.

You would probably be much farther ahead making sure the stock cooling system is all in place and functioning properly then in trying to band-aid on an external cooler. Odds are your engine is a victim of Previous Owner syndrome, so all bets are off as far as whether your cooling system is working as intended.

One thing you should consider when contemplating changing the doghouse housing for an earlier one is that the earlier housing was designed with the assumption that there was an oil cooler in the middle. The old-style cooler was an integral part of the airflow control of the older housings, as it was part of the ductwork guiding the cooling air to the 3/4 cylinder head. If you install the early housing without an internal cooler, then there's a huge gaping hole there where all of your 3/4 cooling air is going to go, cooling off the bottom of your cylinders pretty well, but not doing much good for the head.

The stock system, as designed, was perfectly capable of keeping the engine and oil temperatures under control in a wide range of conditions. What is it about your particular setup that makes you think it's different than the millions of others that were delivered?

In short, slapping on an external cooler to "fix" the problem is throwing money in the wrong direction. Take care of the basics first.

Also, Google "Hoover Bit" to learn about a common problem with doghouse cooler installations.

[ruckman101]

Your temp and pressure niumbers don't seem all that much out of the ordinary. Maybe your running pressure seems a bit low. Are you using 20w50 oil? As Hippie said, 200F is not that hot for oil. In fact, it's too low to boil off any condensation in the engine.

You would probably be much farther ahead making sure the stock cooling system is all in place and functioning properly then in trying to band-aid on an external cooler. Odds are your engine is a victim of Previous Owner syndrome, so all bets are off as far as whether your cooling system is working as intended.

One thing you should consider when contemplating changing the doghouse housing for an earlier one is that the earlier housing was designed with the assumption that there was an oil cooler in the middle. The old-style cooler was an integral part of the airflow control of the older housings, as it was part of the ductwork guiding the cooling air to the 3/4 cylinder head. If you install the early housing without an internal cooler, then there's a huge gaping hole there where all of your 3/4 cooling air is going to go, cooling off the bottom of your cylinders pretty well, but not doing much good for the head.

The stock system, as designed, was perfectly capable of keeping the engine and oil temperatures under control in a wide range of conditions. What is it about your particular setup that makes you think it's different than the millions of others that were delivered?

In short, slapping on an external cooler to "fix" the problem is throwing money in the wrong direction. Take care of the basics first.

Also, Google "Hoover Bit" to learn about a common problem with doghouse cooler installations.

Eh, wadda I know.

One of the things I love about this forum. Constant elucidation of misconceptions. I bow in deference to SlowLane's superior grasp of nuance. I was shooting from the hip.

I, too, wonder if you aren't putting a band-aid on bigger issues.


neal

[urtheiz]

yep, 20/50 castrol. no smoke outa the filler hole. smoke was coming from the oil cooler leaking (where it mounts to the engine) onto the heater box.

[dtrumbo]

Personally? I'd keep the dog house cooler and dispense with any external annoyances with their dozen new failure points.
Colin

I would too (and did on your advice).

Now that urtheiz has posted the reason for the add-on, I have to echo what SlowLane has very eloquently pointed out.

The stock system, as designed, was perfectly capable of keeping the engine and oil temperatures under control in a wide range of conditions. What is it about your particular setup that makes you think it's different than the millions of others that were delivered?

If your situation isn't extremely unique and you have a documented need for additional oil cooling, you are truly wasting your time and money and are most certainly inviting more headaches. I had an external cooler system fail and only by the grace of the VW gods did it not destroy my engine. I've since removed the external cooler, the engine still runs just as cool and all the extra plumbing required for the external system isn't poised to f*** me again. Sorry to pile on, especially after you've said you've already done the deed but cut your loses and restore the engine's cooling system to it's original and completely adequate glory. Good luck.

[urtheiz]

what is hot for oil? 240-280? at times the temp gauge goes there (i may be wrong, but imo, and others at this site, i thinks thats way too hot) at that point i pull over and sit fer awhile (yes i am using 20-50). what eles can be the causes for the heat? carburation? the oil pump (is the OP supposed to be 0-5 lbs at a stop lite? red lite goes on then) everytime i get gas i check the oil (and i change the oil often) sometimed it gets really black 'n funky looking in like 1400-1800 miles, which i've heard is caused by overheating. if the external coolers might end up being more of a problem what suggestions might you have that would cause the overheating (being, almost flat fwy driving, 30 miles @ 65mph and the temps get to 240+) so i can correct it. if you can help set me in the right direction that would be most helpful, thanks

[dtrumbo]

First, is the engine properly tuned? Mixture set correctly, timing set correctly? You can get a rough feel for mixture by looking at the spark plugs. Are they black to brown or nearly white? Whitish indicates a lean condition which means the engine is running hot and you will cook your heads. Your oil never (or shouldn't) gets anywhere near the heads so cooling the oil won't help that particular situation.

If the engine is tuned properly is the rest of the cooling system in place and working properly. Are all the tin pieces installed and is the rubber seal that isolates the engine compartment from underneath the bus in place and sealing correctly? If you stick your head in the engine compartment can you see any daylight leaking in from under the bus? If so, you need to correct whatever is missing/broken to keep the hot air under the bus from leaking back into the engine compartment.

Then to the most important part of the cooling system. Is the fan operating properly? Is the generator/alternator belt on and at the proper tension to spin the fan correctly? If nothing obvious appears from the aforementioned suggestions you might need to pull the motor and remove whatever parts are necessary to inspect the ducting for the cooling air. Perhaps there is debris (mice nests are notorious) on top of the cylinders which is impeding your cooling air. Take off the fan shroud and see what's what. Did some PO do something funky with the flaps that is preventing them from opening and blocking cooling air?

It's a lot of work, but it has to be done one way or another. There is no magic bullet (or oil cooler) that can "fix" a broken or otherwise non-functioning cooling system.

[SlowLane]

Your oil never (or shouldn't) gets anywhere near the heads so cooling the oil won't help that particular situation.

Well, sorta. The volume under the valve covers is full of oil mist coming off of the rocker assemblies, which cools off on contact with the valve cover. Which reminds me: got chrome valve covers? If so, get rid of them and put on some good quality old boring black covers. The valve covers help to cool some of the oil by transferring heat to the outside world. As do the pushrod tubes, which drain oil back in to the crankcase. If either one of those items are shiny chrome, the effectiveness of the heat transfer is reduced and oil temperatures go up.
Same goes for those bitchin' aftermarket aluminum bolt-on valve covers, which, in addition to being leak-prone, place an additional mechanical stress on the outer rocker-arm studs.

Take off the fan shroud and see what's what. Did some PO do something funky with the flaps that is preventing them from opening and blocking cooling air?

Or for that matter, did some PO remove the flaps altogether, in the regrettably common but misguided belief that they impede cooling? In fact, the flaps serve to aim the cooling air at the heads where it is most needed. Even if you don't have a thermostat, properly operating flaps are necessary.

There is no magic bullet (or oil cooler) that can "fix" a broken or otherwise non-functioning cooling system.

What he said.
As far as the black oil after only 1400 miles goes, I suspect it's more a case of oil contamination from combustion products (ie. soot) than from overheating. Even at their best, these engines could never match the combustion efficiency of modern engines. It's a big reason why the oil change interval back then was only 3000 miles.
Oh, yeah, another thing: got a factory oil-bath air filter? If not, there's another reason you get dirty oil.
Did you Google "Hoover Bit"?

[bajaman72]

Personally I would tear the engine down to long block status, mabey even a short block. It seems the overheating engines I have been dealing with latley have greasy/cake/mud/debris stacked on the cylinder fins. Im running cheapo chromie valve covers with no problems. Also mabey check the piston releif valve(s) are not sticking in the bores.