Exhaust manifold gaskets

[Brianpr]

I need to replace the exhaust manifold gaskets on my 400 ISL. I soaked all the bolts for a week with PB blaster and was able to remove them all without any broken bolts! Wondering if I can slide the new gaskets between the block and manifold without actually having to remove the manifold completely? There seems to be a large enough gap/play that I can get the new gaskets between. Would be nice to not have to remove the entire manifold from the turbo and all that that entails. The manifold itself appears to be fine. Thanks for any input I can get.

[n2zon]

Originally Posted by Brianpr

I need to replace the exhaust manifold gaskets on my 400 ISL. I soaked all the bolts for a week with PB blaster and was able to remove them all without any broken bolts! Wondering if I can slide the new gaskets between the block and manifold without actually having to remove the manifold completely? There seems to be a large enough gap/play that I can get the new gaskets between. Would be nice to not have to remove the entire manifold from the turbo and all that that entails. The manifold itself appears to be fine. Thanks for any input I can get.

You need the mating surfaces to be clean and flat. If you can accomplish the first and check the second without pulling the manifold out, go for it!

[Bruce Anthon]

I found that the only way I could get the surfaces really clean and flat was to remove the manifold.

It is common for some of the ISL manifolds to crack where the number 3 exhaust port merges with the manifold. Mine looked fine from underneath the engine but when inspected from above I found a crack that was just starting. Be sure to really look the manifold over carefully… now is the time to replace it if needed. I didn’t see the year of your coach but I also replaced the flexible oil line to the turbo while doing this work.

[ATTACH]387996

[Brianpr]

Originally Posted by Bruce Anthon

I found that the only way I could get the surfaces really clean and flat was to remove the manifold.



It is common for some of the ISL manifolds to crack where the number 3 exhaust port merges with the manifold. Mine looked fine from underneath the engine but when inspected from above I found a crack that was just starting. Be sure to really look the manifold over carefully… now is the time to replace it if needed. I didn’t see the year of your coach but I also replaced the flexible oil line to the turbo while doing this work.



[ATTACH]387996

Thanks for the advice. Any idea on part number or size of the rubber hose you replaced? My cracked open while removing the manifold bolts. It looks like it’s a coolant line though?

[Bruce Anthon]

Pictures would be good. There isn’t a coolant line.. but there is a drain hose that connects the bottom of the turbo to the side of the block for oil return. I ordered it through Cummins By my engine serial number. The oil feed line comes into the top side of the turbo and is a s/steel braided line. I will send you a PM if you need additional info.

[jacwjames]

If you don't have an account on the Cummins Quickserve site I'd suggest creating on and registering your engine using the SN. It has a lot of information on parts and maintenance. You should be able to find a parts breakdown of the turbo lubrication lines.

[Brianpr]

Thanks for the suggestion. I just signed up for Cummins Quickserve. Looks very helpful. Here are some photos of the rubber hose I am wondering about. When it broke, quite a bit of antifreeze came out of the nipple it was connected to. There is a hard line connected to the same location that runs to the engine block. The other end of this line runs to the coolant expansion tank.

[jacwjames]

My system is a little different (I think).

I had a small hose attached to a fitting on the pipe for the thermostat. The small hose went to the top of my surge tank. I replaced it when I replaced the surge tank, it was hard and brittle, probably because of the heat.

There was another small hose that went from the top of the surge tank to the radiator, it was fine so I didn't replace.



Quickserve is a great site once you learn how to navigate around it. When I find a parts page I need I'll print it to PDF and save it my files. I have a lot of info that I've accumulated over the years.

[96 Wideglide]

I think that may be coolant for the turbo actuator. Recall watching a Youtube clip where a guy needed to work inside the actuator, and drained a few gal of coolant before opening it.

The older models may not have that.

[Bruce Anthon]

Mine is an 03 and doesn’t have coolant routed to the turbo. Quickserve is your parts link for the added items. Just be sure to look at the manifold carefully. Good luck.

[Lowflyer1]

QuickServe shows coolant lines for my Aug-03 built ISL 400. It's in section 10.

One funky thing I've noticed on QuickServe is that if I want to print or save a page to .pdf, I need to search and select that item from the left side index. If I use the search function, the "print page" is not available.

[Brianpr]

I was able to replace all manifold gaskets without having to remove the turbo thank goodness. I went for a test drive today and I heard a slight whistle sound at low speeds when I stepped on the peddle. I didn’t hear anything as I got up to speed and set the cruise control. Is the whistle sound just the turbo winding up or is this still a possible small leak near a manifold port?

[96 Wideglide]

Turbo winding up does make a whistle sound, but, if you never heard it before.........?

[DR60]

When looking for an exhaust leak I use a length of rubber hose with one end pressed to my ear and the other run along the exh manifold. this cuts out the other engine noise and lets me concentrate on just the sounds near the hose end. DR