Overheat problem on tamd41

timwitcherley said:
I am running out of options on my targa 33 with twin Volvo 41. Based in Mallorca she has been fine all season, out here for 2 weeks and the starboard engine overheats at cruising revs. They are well maintained and had a complete strip down last year. Mechanic has checked all the normal things, impeller. Raw water intake,all pipes replaced, new freshwater pump fitted. None of this solved the problem so Boat was lifted yesterday to check drive intake etc- all clear!

Has anyone had similar problems or suggest a potential solution - mechanic is running out of ideas!
Click to expand...

Oil cooler blockage
Previous impellor broken up and parts blocking waterways
heat exchanger core furred up
Thermostats opening

Just a case of being methodical I guess and a good engineer will know these things..

Sure others will chip in shortly with ideas, but good luck.
 
I'd say you have a raw water blockage somewhere, has he sea trailed the boat and tested the cooling system for hot spots with an infa red temp gun?.

I'd say it's either a blocked oil cooler as that's the first place sea water will not get through, heat exchanger, rod the tubes and make sure the rubber dividing strips are good cond on the end cover. Intercooler, easy that one to check,

Lastly the exhaust elbow, remove and check fir blockage on inside where rubber pipe fits, also where water pipe from heat exchanger fits, I recently had an ad31 with same problem, he used dealer to no avail, that's all it was and h spent££££ with them on silly things.

Remember it's an old boat, parts just don't work like they did when it was new.

Failing that I'm in Santa ponsa for a week from this sat.
 
Thanks Rob - he checked oil cooler acid cleaned heat exchanger fitted new thermostats and replaced the solid pipe work with flexible - that is where he started on Monday!
Currently awaiting new senders and gauges although he swopped these from port to starboard yesterday and the gauge still crept up (although the alarm didn't sound so this could be a possibility)
 
Follow Paul's advice on the IR temp gun. I've had 2 boats with AD41's and ended up chasing cooling problems that weren't there. Purely due to increased resistance on the cabling. IR gun on the engine showed temp's with 1 or 2 degrees of each other whilst a gauge on one was saying it was overheating by 10 degrees. Best buy ever. Swapping out gauges won't solve an electrical issue if it is in the cabling.

Once shut down an engine on a rough crossing in holland after the temperature spiked.
Limped into a windy marine on one engine only to find out five minutes after berthing that coming of a wave one of the spade connectors on the temp gauge had moved. Pushed it back on completely and the temp dropped by 10 deg to normal.

Rob
 
regarding IR thermometers, I had some trouble with my home combi boiler, that's when I bought one a few years back. I then noticed that the temps it's registering are OK on matte materials (rubber hoses, cast iron bits, etc) but carp on shinny things (copper shinny elbows, chrome plated bits, ss tanks, etc)

Ended up using a permanent black marker to paint spots on them before taking the temp off them.

Most likely you wont be come across such issues, but good to know nevertheless.
You'll be mostly checking on black matte rubber hoses == ideal material for accurate values ;)

good luck

V.
 
I would agreee with VP about the blockage somewhere. I had exactly the same on my old boat with 2 AD41's. just pootling around it was fine, but as soon as you opened it up one engine would overheat. Prob not sufficient flow at high revs. Eventually traced it to a small bit of impellor stuck in one of the bends in the copper cooling pipes which I only found after I'd replaced the thing. Got the old one out of the car one day to take a pic and slap it on ebay and it was only because it had totally dried out that this little piece of impellor fell out. If I remember correctly the first area to check is the oil cooler which is the first place it could get bunged up.
 
Ever noticed that when you "pick" a spot it gets worse not better? Well here's one for you. Yesterday Steve and I removed the intercooler stack from George and cleaned it (it was a little blocked with oil and dust) it was refitted and we started the engine let go the ropes and went out to test it, before we had cleared the creek the temp gauge was on the "up" AND STILL RISING! a quick look over the transom confirmed that the the cooling water was not circulating. Quick turn round and back to the berth. Remove end covers of intercoolers to refit seals, all correct, prime jabsco start engine no good. Remove all pipes and flush try again NO GO!, remove face plate of Jabsco impellor falls out in several pieces. Fit new impellor, prime system, start up, still no water from exhaust. By now tempers becoming frayed, what the hell has gone wrong? Last gasp solution, remove pump from engine and disasemble, and what do we find? the "flipper" plate is completely worn out and not deflecting the impellor blades therefore no "lift". The pump body is cleaned and new back plate, deflector, and impellor fitted, every pipe flushed, then primed, engine started and the force of water exiting the exhaust pipe is almost enough to move the boat without engaging gear. The moral of this tale is do regular maintenance of "all" systems on a strict schedule. Or get caught out at sea and have to fix it out there. Will/Do we? to be honest no we don't, only "fix" it when it's broken, but we have Arthur to rely on. LOL
 
Overheating

I had a similar problem on my previous boat with twin KAD 42s. After doing all that has been mentioned in this thread I finally found the problem. My mechanic had used the wrong (smaller)impeller deflection plate when overhauling the raw water pumps. The owerhaul kit contains two options, one for lower hp engine and the larger one for the Kad engine. The last thing I suspected was the impeller pumps as the were just rebuilt. Anyhow easy to check and fix. Also the learning was to always use properly qualified mechanics.
 
bit of an obscure one but thought i best mention it..........

Impellers can spin on the hub sometimes .

testing in a vice dosent work as the grip of the vice will hold it firm.

If you have removed the impeller, checked it and put it back , or if the fault occurred following a new impeller then it might be worth you switching the impellers or replacing with a new one.
 
If its the starboard engine overheating then this is the one with the power steering pump on it most likely, if so there should be an oil cooler in line with the seawater hose from the transom to the raw water pump, have had blockages in these before, seaweed ect.
 
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