So once again bringing revisiting this issue as I must be missing something. Getting onto the highway at about 3500 rpm the fan exploded yet again. That is third time in roughly 1200 miles all about the same RPM. So quick recap is

So first time it exploded took out a bunch of stuff, replaced, upper and lower shroud, radiator, airbox, thermostat, coolant hoses, and fan. Kept existing clutch (which was about a year old or 3k miles on it). Thought issue was lower shroud wasnt in correctly at bottom and maybe got into fan. Think i was wrong

Exploded again (500 miles later) and this time found some play in water pump (cheap one that i replaced about a year earlier or 3k miles on it). Replaced water pump with airtex, fan, fan shrouds, thermostat, radiator, and hoses. Using same clutch yet again. Check motor mounts and they look new

Exploded yet again (700 miles after second one) and this time it has taken out radiator, fan, hoses (not thermostat this time) fan shrouds and got both an oil and transmission cooling lines. I have ordered parts yet again and this time got another clutch just to take that out of equation i hope

So you can see this hasnt been cheap the last 6 months or so and only 1200 miles later for same issue. Not to mention my hood is dented pretty good after all of this. What am I missing? I checked my motor mounts by slowly raising engine to see if they had separated and I see no such issue. I dont have play in water pump and I dont feel a vibration when this happens its just a loud explosion, plastic pieces out the bottom and then I pull over pretty quickly so as not to overheat and get the rover towed home.

I would like to keep the car but hard to trust it right now. I know one answer is not to get the rpms over 3k which I dont 95% of them time but living in a larger city and using the highway it just happens at times. I consider myself pretty mechanically inclined but I am baffled at myself on this one.

 

Are you using an HD fan clutch? and have you checked the transmission mounts?

 

did have jack under there checking motor and tranny mounts

 

Definitely check motor and trans mounts as drow said. Also make sure you've secured the shroud and radiator well so that they cant move allowing the shroud to come in contact with the fan.

This is the reason I converted to an electric fan setup. I recommend the same to pretty much everyone with fan issues. The write up is in my signature.

You shouldn't be having that problem even over 3k. Even when I had the mechanical fan I would peg it from a stop almost every time I was pulling out, all the way to 5k. Never had an issue.

 

Thinking back I did have HD clutch I installed about a 1.5 years back. When the first explosion happened I believe the clutch I replaced it with was just a OEM non HD clutch. I will have to check my purchase history when I get home but reason I believe that to be true is I did have a lot of fan noise and with newest replacement I do not. My temps have always been good so didnt worry about that to much.

As far as checking engine mounts all I did was just a jack under the motor with a 2x8 and little by little pushed up on motor to check if they had separated. The transmission mount(s) i have not checked but part of me just wants to order all new mounts and replace them

The shroud I am pretty sure is not moving. Before the first explosion I have the lower one zip tied at the bottom because I lost the clips when I swapped in a new radiator way back. I ordered new clips and that rubber seal at the bottom and both times it has still been in place. Once I have them installed I yank around on them to check for play and seems pretty tight with what would guess is .5 to 1 inch of gap between shroud and fan. Seems to be good there that why I was leaning to mounts being an issue

 

H2O pump pulley replaced yet?

May be a long shot but had one break on a '67 Caprice years ago. Never destroyed my clutch but do remember having to replace a clutch sometime before or after the pulley.

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