10-27-2019, 01:37 AM
2005 25' Safari
Join Date: Mar 2006
Originally Posted by Keyair
To the engine overheating question...
Here is my $0.02 based on what I know, and have experienced personally:
1/ The stock cast iron exhaust manifolds are known to be restrictive, hold and radiate heat. Then they warp.
2/ When they warp, it blows the gaskets, and/or pulls the header bolts out or breaks them. The localized superheating warps the manifold worse.
3/ The hot exhaust gases then blowtorch the plug wires, but even without blowing gaskets, the wires are vulnerable to heat damage.
A few things to think about:
1/ Exhaust Manifold, will need to be checked for flange warp, and machined if needed(99% certainty). Bolts need to be replaced and high quality/correct length. High quality gaskets, I heard solid copper gaskets are best. Retorque after a few heat cycles.
2/ Airstream side shields between chassis and body MUST be in place. See notes about cooling and exhaust manifold warpage in the GM P30 Chassis Manual. Without them, the manifolds loose cooling air flowing over them.
3/ Plug wire protective metal shields were installed originally for a reason! High quality, high heat silicon plug wires are mandatory.
4/ I think the '87 had twin smog pumps. Make sure they are present and correct, and working properly... they inject cold air into the exhaust manifold, which cools it. Had a friend who removed his, and he had multiple header warpage issues.
High quality tubular headers/exhaust are well known to aid power/torque on the 454, and ceramic coating is the best thing you can do. Banks Power kit is expensive, but the best.
Make sure your upper radiator shroud is in place?
Good correct, AC Delco Viscous fan clutch?
[COLOR="red"][/COLOR]Is your ignition timing correct?
Is you engine running too lean?
If the 454 engine has an issue and is ready to be replaced, it makes sense to weigh a Cummins swap, but not before, unless you have money to burn.
2005 Safari 25-B
"Le Petit Chateau Argent"
[ Small Silver Castle ]
2000 Navigator / 2014 F-150 Eco-Boost / Equal-i-zer / P-3
YAMAHA 2400 / AIR #12144