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MG MGB Technical - Oil Cooler Cleanout

Hi
Can anyone tell me the best way to clean out an oil cooler. Do I just give it a cocktail shake with flushing oil, or is there some other more exotic way of doing it?
Ken
K.G. Martin

Ken. All of the coolers I have seen had the pipes connecting them frozen in place after they had been assembled for a while. The one time I tried to remove a line attached to the cooler, the top of the cooler split before the line came loose. Do not know how long they had been connected. Hence, I simply replace the lines and cooler rather than attempt to clean them out.

Flushing oil is an interesting concept. I have only used it immediately prior to pulling an engine for rebuild for fear of what it might break loose inside the engine. This was discussed several years ago and there should be a thread in the archives about "flushing oil". That might provide some useful information. Les
Les Bengtson

You don't know what's in there is it just gunge or are there fragments of metal from a previous problem.

Don't risk your engine, throw it away and fit a new one they are not expensive.
Iain MacKintosh

Flushing it in reverse to the normal flow willl be more effective. If you have had a significant mechanical failure or have scored bearings you should replace the cooler as it will have swarf stuck in it.

Some people always change the cooler when rebuilding an engine rather than cleaning it. In the end it is a risk effort cost relationship that only you will be able to answer.

David
David Witham

Ok, I've just had a complete engine rebuild and obviously I don't want any residual bits getting back into the new engine, so I guess it's a new oil cooler. Thanks guys.
Ken
K.G. Martin

About once a year I've used a can of engine flush to fill the cooler and let the cooler sit overnight. Perhaps any decent solvent will do.

Can bits even get into the cooler at all? Does the flow go through the filter before or after the cooler? I've never seen anything other than gunky oil - as if that were not bad enough. I would expect a well maintained oil cooler to last darned near forever. Start with a new one and take good care of it.

Dean
Dean Lake

Dean. Oil flow is from the right side, upper rear of the block to the oil cooler, then from the oil cooler back to the oil filter. Hence, anything in the oil cooler that breaks loose should be captured by the oil filter. But, flushing oil is non-selective. In other words, it cleans the entire system, not just the cooler. Anything that breaks loose, as a larger particle, between the oil filter and any of the various smaller oil outlets can cause a problem because there will be no filter to catch them.

As I mentioned, I have used flushing oil to clean out oil passages prior to a rebuild. The flushing oil seemed to do quite a good job of removing sludge and build up when used according to the directions. When used on an annual basis with a rebuilt engine (starting with the first oil change after one year of operation), I suspect that flushing oil might be a good idea. But, on an old engine with an unknown oil change history, I rarely use flushing oil except as noted. Les
Les Bengtson

Ken -

I've been told to throw tham out and buy a new one. If you clean it you may dislodge crud that has settle out in the cooler and not fully get it removed. Then you stand a chance of pulling the crud in to your moter and cousing damage.

Doug
Doug Brooke (OR)

Last change I flushed mine out with petrol & then clean oil and the junk that came out in the petrol was unbelievable! Yes, new coolers are cheap, except that since rebuild more years ago than I care to remember I have used a bigger oil cooler than standard (I havent counted the rows, but its about as much bigger than a chrome bumper standard one than a chrome bumper one is bigger than a rubbe bumper one). The engine is a 3 bearing and I don't want it to run too hot in traffic in summer. The oil will probably run hotter anyway as I packed the pressure relief valve to get an indiacted 80 psi. The engine is fully balanced and this has worked a treat for 50,000 miles.

John.
John Prewer

Just to clarify (no pun intended), I use the flush stuff in the cooler only - not in the engine. I did use the flushing stuff once in a basket-case engine and it did no real harm, but no real good either. Any engine of mine that I've had from new or rebuilt will never see a can of engine flush. Won't need it!

Dean
Dean Lake

I stick the hose from my parts washer in one end of mine and walk away. Sometimes it flushes all night. Afterward, I have tried running a solvent through them and the stuff came out clear. FWIW
gerry masterman

I have to agree with Iain here. With all the time and money you've just expended on a rebuild I'd suggest a new one. And new hoses too. Just my two bits.

Paul
Paul Hanley

Thanks guys, I have ordered up a new 13 row cooler with stainless steel braided lines..........which leads to another question. I cannot find the actual amount of oil that's needed in the Haynes manual - tells you everything else except the quantity - I seem to remember it's about 4.5 litres (8 pints) but is that including the oil cooler.When I fill her up for the first time and turn it over (no plugs in) I obviously don't want the cooler sucking up a pint or so away from the engine leaving insufficient oil to circulate to all points.
I've also ordered up a new clutch kit which will be another adventure. This car better behave after all this!!
Ken
K.G. Martin

Compared with an engine rebuild price, the cooler will be marginal in price hence, get the occasion to install a thermal sensor onto this circuit. And good new, today engine oils don't build up so much depots inside engine oil galleries, as it happened during the 60', they are more detergent.
regards
Renou

You people all have deep pockets! A rebuilt engine will cost about 500 or 600 UK pounds, less if you do most of it yourself. A new oil cooler and hoses will cost in the region of 50 uk pounds, so about 10 percent. Everytime I see any comments about reusing things here it seems to be "throw it away and buy new" because it's only a small expense. This atitude will however lead to much higher total bill, by the time you are done you are done throwing away all those bits "just in case". If you can expend a little effort and get the thing cleaned then re-use it and go and buy yourself a beer with the saved money! If you don't want to put in effort and don't care about the money then just send the car to a specialist and just enjoy driving it afterwards!

FWIW
Iain
I D Cameron

There's a lot of sense in that. I guess this a case of "should" vs "must". In my case I probably "should" have bought new, but I "must" spend less on cars. Parafin swilled around in the cooler until it came clear and a good oil filter were my compromise and I still sleep at night.
Steve Postins

I appreciate your comments guys,but relative costs was not the question. How much oil do I pour down the spout prior to start up?
Ken
K.G. Martin

K.G.

Seems to me last time I rebuilt, I just put a small funnel in the oil cooler connection and filled her up before that first turnover. Seemed like a headstart for the oil pump. I probably could have filled the lines too, but I didn't. Maybe I was thinking about the mess - since they don't run exclusively downhill from either direction, something would drip. If I didn't have an inverted oil filter, I'd have filled that up too.

Anyway, with the spark plugs out, coil primary wire disconnected and oil up to the "full" mark on the dipstick, spin her over until you get pressure. The amount of oil taken by the oil galleries and filter aren't going to be enough to drop your level below the "add" mark. After you get pressure, check oil level and add as necessary.

Not the answer you wanted, I know. But it's a reasonable workaround.
Matt Kulka

Good idea Matt, thanks.
K.G. Martin

John Prewer: than I care to remember I have used a bigger oil cooler than standard (I havent counted the rows, but its about as much bigger than a chrome bumper standard one than a chrome bumper one is bigger than a rubbe bumper one).

I plan on switching my oil cooler over to a larger then standard model myself John, I've found one with a built on fan unit and adjustable temp sensor from JCwhitney.com for a little more then the Moss unit the PO had installed on my B. It'll be able to keep the oil temp down much better then a normal unit would.
CJD Dark

CJD - I'll e-mail you this weekend (I'm typing this from work!!!).
What you are planning sounds good, I use a 1960's electric fan mounted just behind the cooler and the car runs sweetly except in traffic, although it's much better since I replaced the radiator a couple of years ago.
John Prewer

CJD

Which model are you looking at? Is it the EMPI ENGINE-COOLING FAN AND OIL COOLER KIT, SKU 48ZX9345U? It is not clear to me how you would mount this unless it is in front of the radiator.

Thanks

Larry
Larry Hallanger

Holy cats! 10" x 16" is quite an oil cooler. You Texans do everything big, don't you?

As Larry asks, where will you mount this except in front of the radiator? If so, you're going to be cooling the radiator with hot air. I'm no expert but I'd think the primary cooling agent should be the water system, since it has a wider flow through the engine, (and I think water throws off heat more quickly than oil).

Maybe for the winters you could mount it in the footwell for toasty warm toes.
Matt Kulka

The oil cooler on MGB's is a "standard" or
"generic" industrial type cooler and can be found
in many sizes and can be gotten from many
sources - including some aviation parts suppliers,
and so-called "hard core" auto racer parts, ie:
Earl's Performance.
Daniel Wong

When I changed my oil cooler and pipes I just cranked the engine for a few seconds with the coil disconected , the pressure came up as quick as after changing the filter . When you see racing Bs the oil cooler is always mounted under the front apron , so the rad gets lots of cool air. Of course you don't get the oooh factor then when you open the bonnet . Mine has red twin air horns there as well clogging up the airflow , but pretty .Finally , I have used flushing oil on an old Citroen it was a performance and you have to check if it's OK first (eg the old Honda V6s had such narrow oilways crud could block them) . Anyway a load of gunk came out , no harm done and it did quieten the thing down a bit .
S Best

This thread was discussed between 22/03/2004 and 27/03/2004

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