Exhaust Elbow

[CRYSTAL]

Hi guys,
What's the easiest way to clean inside the elbow? I removed it and seems quite ugly for 700hrs run time.
Trying to soak with kerosene but not helping. So now leaving for 24hrs to soak more.

Must be combination of rust, soot, etc...  If compressed enough, i am sure I can get a diamond out :-)

Tnx,

[Symphony]

You might find soaking in brick cleaner helps plus physically chipping. Be wary of the casting being fragile through corrosion.

Way to reduce coking up in future is to run the engine hard under load. light running at lower revs and not fully warming up under load is not good for the engine.

[CRYSTAL]

Cheers.
I got all the black crap out from the elbow but very conscious about chiselling as the elbow is double chamber.

Is there a way we can slow down the corrosion or it's inevitable that the elbow will be replaced at one point?

Posting some pics but missing elbow pic... be nice to have a probe cam.

[Nigel]

Posting some pics but missing elbow pic... be nice to have a probe cam.

This is the best snake camera I've tried: http://amzn.to/1h2yzjC

I went through the side of my elbow with a screwdriver, the metal was paper thin. Best that it happens when you know about it.

[Spirit of Mary]

My local VP dealer has several times said to me that I should change this elbow preventive. In 8 to 10 years most of them are corroded through. Problem is you can't see it from outside.
Next problem is you have to get it from Volvo and than you know you pay the extra price!!
gr,

Ger

[CRYSTAL]

Thanks Nigel,
How old was your elbow?
Or how many hrs on it?

Isn't there a way to customise this part with stainless steel?

Tnx

[aquapore]

I am having the same problem. The cast iron is very heavy casting and I presume Volvo intended to allow for corrosion in the service life.

That is no consolation.

I have cleaned the elbow by soaking it in a solution of about 10% EDTA (ethylene diamine tetra acetic acid - sodium salt) this is a common cleaning agent for metal corrosion products.
Other cleaning agent is sulphamic acid. Both these products are sold under a plethora of trade name - look at the fine print on the label. Industrial chemical suppliers may offer you a sample if approached the right way.

As for slowing down corrosion - I am contemplating dip coating the whole elbow in an industrial epoxy paint. If you warm the elbow to say 50 Deg C first, before dipping, the paint will drain better, and the epoxy will be stronger and cure quicker,  Care must when positioning  the  elbow after dipping so that paint does not accumulate in narrow passages.

I expect to do mine in the next day or so. Will keep the forum posted for those that may be interested.

Aquapore

[CRYSTAL]

Gr8 idea and I thought of doing something similar but I gave up and refitted the whole exhaust with new seal along with the newly cleaned exchanger / O rings. It was a bitch removing / reinserting it again. No leaks and ready for the next sea trial tomorrow.

I hope ur epoxy works as rust usually likes to eat through everything ..... but if it slows down the deterioration , why not.

Thought I update this :-) since all is back to normal.

Replaced thermostat (original in ok condition ).
Lots of filth In the entry of HE.
Removed and fully cleaning the HE and exhaust elbow with new seals.
Also moved the expansion tank much higher and added shutoff valves for isolating the hot water heater in case of leaks. No point of heating the water in the summer months in Cyprus :-)

Engine tested running at 2500rpm for 4hrs about 15mins on full throttle. 3200rpm.

Hope this helps.

Regards
Hratch