Volvo 4.3 exhaust or intake manifolds?

My '99 4.3GL slightly overheated (shutdown before warning tone). But I think I did not let the engine cool long enough because shortly after resolving the raw water pumpt problem, the engine ran rough and would not idle. After sitting a day, I have water in all but the front pistons on both sides and water in the oil from leakage. After purging the water and several oil changes the boat will run fine above 1300. Compression checks out so I/Marina are sure the block and heads are ok. I assume the manifolds/risers are the problem, but how do I eliminate the intake manifold with some simply logic? The Marina thinks it is just the gaskets between the manifolds and risers as they are rusty. But they did not do a pressurized bench test, the filled the jackets and did not see any leaks after several hours.

Re: Volvo 4.3 exhaust or intake manifolds?

Hi ar_be!! realy the only safe way is to do a pressurized bench test on them, and the rizers i don't think you can press test them (not 100% sure) no way to block off were the water and exaust meet. but the mans can be tested. You can do it yourself if your handy with making a plate and gasket to block off were the rizer goes and addapt a hose too it were the water comes in, you can even addapt a air fill in the plate so you can put air to it. I myself just had this problem but the water sat in the motor for a over a year and had to do a complet rebuild But my boat was ran in salt water before i perch it and it realy ate up the mans and rizer so i just bought new ones and its a 1992. but in Illinois no salt!! not to be smart but it get cold up here are you sure it was winterizer properly? . but if you find no prob with the man a rizers and it gets water in the pistons eather there are crackes in all the cyl walls but you say when it sets is when you get the intrution that tells me it is eather the mans or rizers water is going down threw the valves into your heads and into the cyl . but like the marina says it could be the gasket between them. I would get them tested if i was you, you do not want to be in my hip boots Hope i helped and God bless!! Dodge

Re: Volvo 4.3 exhaust or intake manifolds?

Thank you for your feedback Dodge. I'm confident the problem was an over-heating problem due to the amount of time the boat ran on the hose in early May. Did have any issues until the over-heating. I'm hoping to determine what symptoms you see with a bad intake manifold versus the exhaust man/risers. Best wishes...

Re: Volvo 4.3 exhaust or intake manifolds?

Please let me know what you find Thanks and God bless !! Dodge

Re: Volvo 4.3 exhaust or intake manifolds?

Unlikely to be intake, but if you drain your system and then disconnect the water line from each ex. manifold and plug the end of it, you can then remove the feed line from the thermostat housing and pressure test your cooling system with one of the auto kits. That said, an easier look would be to check your plugs after running. <br /><br />Water in the back cylinders only is almost classic exhaust ingestion. How old are the risers and manifolds? Are they original? If the sealing surfaces are thin (less than 1/4" thick) and rusty replace them. If you can see rust lines running from the joint on the outside, you can bet they're running on the inside as well. If the shop you have it at thinks they can be cleaned and reused, find out what happens if they're wrong, i.e. make sure they will stand behind it. Search the internet about risers/manifolds and you will be amazed at how many engines get killed as their owners tried to squeeze one last season in on them. Filling them up with water and watching them won't tell you anything a) no pressure b) not at operating temp. $600 for new risers/manifolds beats several thousand for a new engine all day long...