PDQ OWNERS FORUM

Heat exchanger overhaul on a 75 hp 4jh3-te Can the bundle be pulled out the front without disturbing the rear end cap? What is the best method of cleaning? (ultrasonic is not available) .Does anyone have the o ring/gasket part # handy?

Correct way to check engine oil and transmission fluid, (dead cold or warmed at operating temp)?

Am I correct in thinking the trans is a ZF 25A? (Boat is 2003 model)

How much bottom paint is typically needed ? I will be using Interux Ultra.

Can Kobelt controls be throttled up without being in gear ? (Would like to clear the turbos when at the dock) Do they pull out like a Morse control ?

Engine room blowers, should these be run as needed or all the time( I have been told the later, which I find hard to believe) ?

I plan on purchasing a backup Danforth fortress anchor, what size is typically used , this would be used in foul conditions only, primary would be a Rocnar.

Thank you for any and all sage advice.

Cheers Carl

Carl,

Here is my take on some of your questions:

I have pulled the heat exchanger bundle out the front, but you need to cut some of the fiberglass away that interferes. It is not a big deal.

You might be able to stretch 3 gallons of bottom paint for 2 coats, but 4 is safer.

My lower helm control handles can be pulled out and the speed increased while in neutral. The upper helm does not work that way on our boat.

I only run our engine room blowers to test that they still work. They could be useful to pull excess heat out of the compartment, but I have never felt the need to do that.

That's all I can help with.

hi,

heat exchanger: i've done this 3 or 4 times over the years. in theory you could but you'd risk dislodging the o-ring on the rear end. i always took both off. when you do mark the bundle relative to the housing because end caps have a ridge which needs to match the bundle. marsh harbour boatyard flushed ours. i believe they used muriatic acid. last time i did it in stuart , radiator shop did it. they found bundles loaded with infamous "black goo". once removed made a huge difference in engine temp. you're a 2003, so are we, and the engine numbers published having the goo did not include ours but they were wrong. my records show o-ring as 24321-000750 but i'd double check.

trans: ours is zf25A, so i assume yours is too. what hull number are you?

kobelt: this has been discussed recently on this forum. on our boat, hull 23, lower helm can pullout in neutral but not the upper.

engine blowers: we run if we're going a long distance at full crusing speed. on our boat it makes some difference.

do you know prop dia & pitch?

good luck with the boat.

Carl,

Removing the heat exchange core can probably be done as Duane says, just from the front. It clearly worked when he did it. When I did mine, I pulled the rear cap also. There is are two gaskets in the rear one of them controls the flow of the water. The flow control gasket could be damaged when pulling the core from the front. I would recommend taking the rear cap off and replacing both gaskets. When I did mine I was expecting the seawater side to have crud in it. The seawater is inside the tubes. They were clean but the outside of the tubes we covered in a greasy like slime. I cleaned that off with brake cleaner which took several cans. The port engine been running a little warm in the summer, around 190. That was four years ago and it has never run above 170-175 since.

I believe you are supposed to check both the oil and trans fluid warm. I sometimes check the oil cold and it does not seem to make a difference. I would recommend, for an accurate reading, that you pull the dipstick, wait about 30 seconds and then check the oil. Apparently, it reads low if you just pull it out and read it. If you search through the forum, you will find some threads on oil filling. It seems these engines will go from full oil to half a quart low very quickly and then hold at that level. As a result, some owners don't bother quite filling all the way. I am generally in that camp. Our transmissions don't leak and to be honest, I only check the fluid about once a year. There is a label on the transmissions and engines identifying exactly which ones they are. I think the are ZF-25A's but check it.

Run the blowers only as needed. Hot day, I run them for a little bit after a run. Cool day, I don't run them at all. Diesel is not the threat gasoline is. The only reason I have ever heard to run them all the time on a boat is to be sure the engines get enough air. I don't think you will have that as an issue on our boats. I certainly have not.

Alan

Thanks to all for the info . She is hull # 28. If all goes to plan will be taking ownership later this week. WE ARE EXCITED. So I never count my chickens until!!! and the fat lady hasn't sung quite yet.

I will quietly study the forum info and continue to get my ducks in a row because we are going to have a long ride home. I look forward to giving back as well as taking away. A good active forum is invaluable to those of us who swing our own wrenches as well as enhancing the value of subject.

Cheers Carl (somewhere on the PDQ learning curve)

Carl,

Welcome to the PDQ owners group. It is a great forum and friendly owners when you meet them in person. If you don't mind my asking, where does your trip begin and end?

Alan

hi carl,

why are you so interested in the heat exchanger bundles (i.e. survey,...)?

I used a recirculating pump and ran Barnacle Buster through the system for 24 hours. Does all the raw water exchangers.
I have the pump system (the size of a 4 gallon pail) made by Port-o-flush jr.

That keeps my system clean.
The rear gasket; if not installed correctly, will slip and causes the engine to overheat at only rpms over 3000 .At lower rims there is no indication of overheating.

Wants to run on the wrong side of normal at anything above 3000rpm, every thing points to restricted flow , bottom clean, props clean ,loaded heavy , turns 3800 WOT no sweat but heading for 190+ after about a minute . Backed it off quick returned to normal range. Madeira Beach to Mathews Va. Boats in good order but has had little use since Feb. this year as current owner was stuck north of the border.
Impellers are due for renewal but that would be too easy.

Cheers

Carl,

You seem to know what to look for. Good luck.

Any chance the port engine runs hotter than the starboard?

hi carl,

get a heat gun and check the rw temp in and out of the heat exchanger when it's running hard. i believe the out should be about 20 degrees warmer. if they are almost the same then the bundle has a problem. rw tubes will show blockage right away. fw between tubes is harder to detect a problem.

when we run for hours on end at 3400 our starboard engine holds steady at 195.

Since we are having this engine cooling discussion, keep in mind that for boats (like ours) in southern FL in summer where the water temp gets close to 90F, it will definitely have an effect on engine cooling. That is not likely affecting you right now, and won't be as bad in VA, I assume.

Another consideration is that antifreeze/coolant is not as effective at removing heat as pure water. If freezing is never a concern, you can run just water with the proper anti-corrosion additives and improve cooling.