Oil \transmission fluid cooler maintenance

[mrsrobinson]

I took some time today to study the oil cooler and raw water line in/out of same on our V-Drives. It looks like the engine oil and the V-Drive both have a hose running to the cooler (well, what I think is the cooler). From the cooler the raw water hose goes down to a plastic looking tube, 4-5" long attached to the V-Drive and then back to the raw water pump (I think, I lost it when it went under the engine, assume it's the hose coming back).

We have 3 seasons, 200 hours on the coolers. How often do these need to be replaced? Is there any regular maintenance done on them?

They are new to me, just trying to understand them. Why do our boats have these...because of the high rpms they run at?

Thanks

 

[The W.A.V.E.]

I just replaced the starboard side motor oil cooler. I believe, from what I have seen on my 7.4's that the v drives have their own cooler forward on the engine. The oil cooler I replaced was aft which would be the front of the engine. the cooler was located starboard side of the starboard engine.

I just replaced the one...$264.00, because a mechanic told me that the oily film my exhaust water caused on the surface of the water was due to the cooler leaking.

Now he is not my full time mechanic, and he is looking for work if you know what I mean, he said every two years I should probably replace them. I dont agree. I dont know for sure, and I have read my newly purchased engine manuals to no avail, but I believe the one I replaced was the original 1999 unit. Cant be sure.

However, if you have one fail......and you are cruising at 3200 rpm, you wont know till its too late, it will literally pump the oil right out of your engine if it has a total failure.

The v drive cooler sat horizontal on the rear side of the engine forward. I am only assuming your are the same.

Good luck, hope this helps a little.

 

[mistercomputerman]

I just replaced both oil coolers, both transmission coolers and both heat exchangers. They were original to the boat which is a 2001. One of the transmission coolers failed pumping water through the transmission. Then one of the heat exhangers started leaking coolant into the raw water side and could not be repaired. I am thinking a 5 year replacement cycle might be prudent.

 

[mrsrobinson]

I followed the raw water hose coming off the heat exchanger (front of the engine, stern of the boat) towards the bow. Looking down on the engine, facing towards the bow, right about where the trans and engine meet I see a black metal tube looking thing with 2 lines/hoses (look like hydraulic hoses) running into it. The raw water hose travels into and through this. One line goes to the remote oil filter and the other goes down. I could not trace the end. Reading your reply my guess is this is the oil cooler and the other line/hose runs back into the block?

The raw water hose continues towards the bow and enters into a white/grey looking tube, exists this and then travels towards the stern after that. Is the the V Drive trans fluid cooler?

 

[The W.A.V.E.]

What you described sounds like your v drive cooler, sitting horizontal on the back of your engine two hoses connected etc.

 

[mrsrobinson]

Yup, it sits horizontal on the rear of the engine. I swear one of the 2 lines attached to it was running to the remote oil filter. The other line went down towards the bilge.

Any idea what the vertical white looking tube is I see sitting on top of the V-Drive, closer to the firewall? The raw water lines runs through it.

 

[The W.A.V.E.]

I would need to look at it again, I dont remember the white line, but I will tell you I didnt know anything about the coolers until the mechanic told me I needed to replace one.

I didnt know where they were located so I ordered one and when I got it, and seen what it looked like, I started looking for the part in the engine room. I started to dissassemble the vdrive cooler by mistake because it looks similar to the engine cooler but not exactly. It took me another 15 minutes to find the engine cooler, it sits real tight against the front of the engine and sits vertical not horizontal.

Good luck, your probably due to change them out.

 

[J Levine]

Typical setup on a mid 90's Merc 454 V-Drive has the raw water line comming from the water pump rounted first to the transmission oil cooler that is mounted vertically and strapped to the transmission with hose clamps and then to the engine oil cooler which is mounted horizontally on top of the bell housing between the engine and trans.

 

[The Bill Collector]

I just pulled out both of my transmission heat exchangers and took them in to my local old school radiator shop. Both were hot tanked and pressure tested ($200 total) and back in the boat working perfectly....

 

[mrsrobinson]

Typical setup on a mid 90's Merc 454 V-Drive has the raw water line comming from the water pump rounted first to the transmission oil cooler that is mounted vertically and strapped to the transmission with hose clamps and then to the engine oil cooler which is mounted horizontally on top of the bell housing between the engine and trans.

Ahhh I think the light just went off. Rethinking this it makes sense now. The raw water hose coming off the raw water pump goes to the V Drive first, running under the engine alongside the stringer...correct? From there it runs to the vertical V-Drive cooler (white looking thing) then up to the oil cooler then back to the heat exchanger. If correct then it all makes sense now.

Is the removal/reinstall of both coolers fairly straight forward? Any "make sure you do this first" kind of things?

Regarding bonding/zincs in this system, what should I be looking for?

What's a good source/store for buying replacements?

Thanks

 

[Hampton]

If you fresh water rinse the cooling system after use, they will probably last forever. I just replaced mine (3.5 years old) right after installing my fresh water rinse manifold, so now they'll last.