Dual Thermo Crossover Pipe

[IronMike]

I just installed the HO water pump (no problems) from Penisular with the dual thermo cross over pipe. As with some of my do-it-myself projects, there was a water leak at the mounting flange on the crossover pipe. Removed it and found the pipe cracked. So, with my motor tech skills in gear, I removed it and installed the old single thermo crossover. Same thing happened.
Duh!!
The mounting bolts started after some trying during each installation but they were not easy go. I did use antiseize compound when installing. But the bolts were a little hard tightening up. Am I supposed to use a water sealer on these bolts?
Anyone have any ideas?
I know, use a tourque wrench, dummy. But the inner bolts are so hard to reach. And that was the stress area where the pipes cracked.
Also, I did apply sealer to the pipe mounting gaskets. Was I supposed to or not?

[tommac95]

Hi Mike
I've only (re-) installed a thermo hsg for a single thermostat. Mine leaked prolificly the first two attempts (lost a gasket or too). Then i carefully flattened the bottom flange using silicon carbide watersand paper on a flat surfaceplate ... final mounting was/remains DRY.

More Power suggested using (flat) washers on the fastenings securing the aluminum intake manifold , as a number of folks have lost bolt tabs on them while torqueing on the I.M. I doubt there is room on the thermo flange for washers, but maybe....

I strongly suggest procuring a 10M X 1,5mm pitch tap to clean the threads in the heads for accessory mountings. The neversieze just masks the friction caused by dirt/corrosion/burrs. Also 'clean up' any burrs on threads of fastening with a (preferably triangular) file pre-assembly. The intake manifold gaskets , and some of the thermo-hsg gaskets are quite thick , which allows a seal when parts are at varying distances from each other. Unfortunately this additionally presents the possibility for the flanges to bend during the torqueing process. I'd suggest tighten the bolts/studs real slowly , alternating from one to another while monitoring the gasket compression. I vaguely recall needing deep socket(s) and universal-flex adapters to install the thermo hsg....

I almost never install any engine-fastenings without either one of the following on the threads: Loktite , silicone RTV , a lubricant (as Neversieze). For thermo hsg i think i used RTV , but i do believe that Neversieze gets the best results for that application.

[IronMike]

Thanks a lot for the advice, Tommac95.
I will tap these holes before I attempt my next install.
'Preciate your help....:)

[oilburnertoo]

Make sure all the old gasket is off the head surface, the old gaskets are pretty hard material and tough to scrape off.

[More Power]

Good memory Tom! :)

I broke a mounting ear on a coolant crossover back in the 90's while torquing a bolt. Since then, and as Tom mentioned, I've used a steel flat washer under those bolts.

A broken ear can be TIG welded, then the joint can be block sanded to get it flat.

I have also found that those bolts need to be re-torqued a week or two after installation to produce a long lasting and leakfree install. The gasket compresses over a few days, relaxing some of the initial bolt torque.

Jim