Is this second tube with yellow rubber cap for oil change pump?

[YeOldeStonecat]

I've been reading up on changing oil in the 5.7's...that there are pump kits out there you use on the dipstick. While some articles or reviews or opinions say they don't get enough old oil out, and can't suck up the sludge that accumulates on the bottom of the oil pan, I think these pump kits will still help me in that I'll change the oil more often anyways..and perhaps have the marina do the "full" oil change every year or two that gets the bottom sludge out.

So..I've read the pumps utilize the dipstick tube..and that there are also optional "larger diameter" tubes that allow the pump to work faster...instead of trying to sip it all out through a skinny straw. I notice my engines have a second tube with a yellow rubber nipple on them? Is this an add-on kit for the pump kit? Each engine has one, and they appear to be at the same fore/aft level as the regular dipstick.

I'm also concerned with what appears to be some engines thirsty for oil. I checked the oil levels before doing a 2 hour ride out (and then back) across the sound last weekend, they were 3/4 low so I topped both engines up. About 6 weeks ago I topped off starboard engine with almost 1 qt. But I notice prior owner appeared to use 10/30 oil based on seeing oil jugs in one of the storage lockers. Wondering if that oil is just too thin, appears Merc recommends 20/40 or something thicker. We closed on the boat end of June, engines around 600 hours. While the bilge isn't the cleanest around (I'm working on it)...appears to be just typical 20 years of built up slop 'n sludge down there, no free running wet oil that I can see...so I'm doubting a leak. Had compression test done on one engine that backfired a lot from the sea trial (ended up replacing distie and rotor and wires fixed that)..comp test results were decent..2x cylinders with a hair lower than others but mechanic said within 15% margin.

Recommendations on pump kit that does the best at sucking out all the old thicker oil that accumulates down in the sump pan?

Below pics taken after hosing her down hence why it's all wet in there. Dipstick is obvious..with the yellow loop handle, but opposite it on each engine, is what looks similar to a dipstick but has the yellow nipple on it.

 

[Stee6043]

I believe the yellow cap is the "other dipstick tube". The motors can be installed in either orientation (stern drive vs v-drive). They put dipstick tubes on both sides just in case.

I wouldn't worry too much about the speed of the pump. There are plenty of other things to do while the pump is doing its thing. I use the cheapo pump below and it'll drain an engine in 20 minutes or so. Just make sure you get her good and warm. Plenty fast.

https://www.amazon.com/gp/product/B01KZIFZVK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[Lazy Daze]

On the "assumption" that there is sludge in the bottom of the oil pan... Draining the engine won't get the sludge any better than sucking it out will. Run the engine with Seafoam for a while if you want to get rid of sludge.

The difference in the amount of oil drained out vs sucked out can be measured in single digit ounces. Close enough as makes no difference.

The dipstick IS the "largest diameter" tube you can get to suck the oil out... how would you get a bigger diameter hose into the dipstick?

 

[YeOldeStonecat]

Ahh..gotcha, that makes sense re: having them for either orientation, so you can reach both by lifting just 1x hatch. Thanks. I supposed they do look like the same diameter..and I'll assume they both reach the same depth.

 

[YeOldeStonecat]

The dipstick IS the "largest diameter" tube you can get to suck the oil out... how would you get a bigger diameter hose into the dipstick?

I wasn't sure if some custom kits had a wider diameter tap where they go into the engine sump.

 

[SeadawgVB]

Notice the wide ring just below the yellow cap or actual dipstick; it's threaded (I believe garden hose thread). It is where some of the waste oil suction pumps attach to. These are not your normal Chevy dipsticks, the are actually routed to the bottom of the oil pan and connect to the lowest point. As stated above, if you run you engine(s) until the oil warms up (Check by touching your oil filter.) and then let it drain down into the pan, you'll be able to suck out more than 99% of the old oil.

Sucking the oil out using the garden hose adapter or connecting the vacuum line to the dipstick tube directly above the threaded adapter (what I do) is MUCH better than sliding the skinny plastic tube down inside of the dipstick. The skinny tube down inside of the dipstick is, what I would guess, in case you have a normal style GM dipstick the enters into the motor on the side of the block (like the 4.3L V6 I used to have).

 

[gdavis67]

Been sucking since 1999 and no problems yet! I'll let you infer what you want from that statement. I use the hand pump style that is available at any marine store. Pump it ten times and walk away to do another chore. Come back and the jug is full and pan empty. Works every time. As mentioned before, heat is your friend so let the motors get good and warm.

 

[tony1b2000]

I have 3 types. My favorite and least messy is :

https://www.defender.com/product3.jsp?path=-1|10918|2349116&id=122092

a bit pricey, but no mess. I use 9 quarts for each engine. This really works well. The best part is the pump goes in reverse so you can put the old oil back into the original oil gallon containers for transport to a recycle center.
I have no luck with the hand pump ones. The reason is once you get a air pocket, you have to pump again and again...

 

[JVM225]

I have 3 types. My favorite and least messy is :

https://www.defender.com/product3.jsp?path=-1|10918|2349116&id=122092

a bit pricey, but no mess. I use 9 quarts for each engine. This really works well. The best part is the pump goes in reverse so you can put the old oil back into the original oil gallon containers for transport to a recycle center.
I have no luck with the hand pump ones. The reason is once you get a air pocket, you have to pump again and again...

That’s the pump I have used for years now with no problems. Current boat has reverso system, but I still use the Jabsco on the kids boat and friends boats.

 

[YeOldeStonecat]

Whelp..I purchased the hand pump one, looks like a big wide bicycle tire pump. Has a garden hose attachment to screw onto the dipstick tubes securely with a tight seal. Was on sale for about 60 bucks at West Marine.

I warmed up the engines prior to changing the oil.

Changed the oil filters first, pre-filling each one about 3/4 of the way.

RE: the oil exchange pump...gotta keep pumping...kept pumping for near 15 minutes until it appeared to not be sucking out any more.
On each engine, it took about about 3 qts.
Prior to removing the oil, I already swapped out the oil filters..which are on the high mounts above the engines, nicely accessible. Prior owner had on the medium size oil containers, I got the larger size deeper filters..figure it would hold another 1/2 a qt. West Marine was out of the Mercury brand ones, so I got what appears to be in the West Marine in-house brand, Sierra.

My engines, 1997, appear to be an odd year for manufacture..each holds just 4 qts. I'm guessing 4 qts PLUS whatever the filters can hold. So I was close to 5 qts once oil was in engine, and filters on, and I had started and run the engines a few minutes.

I'm feeling about 1 qt of oil was left behind in the engines. Doing dipstick checks after starting and running the engines for a few minutes post oil change...the oil on the dipstick was still quite dirty looking. Was expecting nice clean oil on the dipstick.

To make me feel better about it I'll probably change the oil one more time in a few weeks just before they haul her out for her long winter nap.

 

[Lazy Daze]

There's nothing inherently different about your engine compared to all of the other small blocks out there that should account for a quart of oil still left in the pan. The "close" to 5 quarts that you put into the engine (with filter... especially a remote filter) sounds pretty much spot on.

I have a MityVac hand pump (from your description, it sounds like your pump is very similar). I don't need to do anywhere near the amount of pumping you do. In fact, most of the time I just pump it 10 times and that pulls it all out... sometimes I give it another 10 or so pumps. Either your pump is defective (or just not very efficient) or you weren't making a good seal at the dipstick.

 

[YeOldeStonecat]

I have a MityVac hand pump (from your description, it sounds like your pump is very similar).

This sucker here...normally 69 bucks I guess, but I got it on sale for 54 bucks Saturday (sale ended yesterday)
https://www.westmarine.com/buy/west-marine--manual-oil-extractor-6-5l--11047123?recordNum=1

Would have heard a bad seal at the top of the dipstick ..and the screw on fitting compressed on very tight. My remaining guess as to poor "evacuation" of all the old oil, maybe I didn't let the engines get hot enough during their pre oil change warmup. Just idled at the dock for 5 minutes with a couple of brief bursts at the end.

 

[SeadawgVB]

This sucker here...normally 69 bucks I guess, but I got it on sale for 54 bucks Saturday (sale ended yesterday)
https://www.westmarine.com/buy/west-marine--manual-oil-extractor-6-5l--11047123?recordNum=1

Would have heard a bad seal at the top of the dipstick ..and the screw on fitting compressed on very tight. My remaining guess as to poor "evacuation" of all the old oil, maybe I didn't let the engines get hot enough during their pre oil change warmup. Just idled at the dock for 5 minutes with a couple of brief bursts at the end.

I run mine until the oil filter is warm to the touch, probably more like 10-12 minutes at idle.

 

[rondds]

I've used them ALL on 4 different boats. The one Tony refers to in post #8 is by far the best and closest you'd get to a Reverso system. Sucks 8.5 of the 9 quarts in my 8.1 in 2 or 3 minutes. Then reverse the switch and pump the oil in to empty jugs - no funnels or spillage.

 

[Lazy Daze]

Depending on ambient noises, you may not have heard a slight leak. It's not always loud. 5 minutes usually isn't enough to get it warm. Feeling the engine or the filter is the most reliable method.

 

[Leardriver]

Buy a $29 2 gallon Shop Vac at Walmart, and use it only for fluid extraction. The suction pressure is light years stronger than any hand pump. Store it in a hefty bag. Use duct tape to reduce the nozzle size down to the tube size. Works very quickly.
I'm not opposed to pouring a quart of oil in after the first extraction in order to dilute and rinse out the crankcase.