The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Coolant temp sensor and exhaust manifold gasket interference

tucsonjwt · 06-07-2019, 02:25 PM

Yes, I was not thinking about how the engine would be shipped by the rebuild factory.
According to the previous owner, a Chevy dealer installed the reman engine and SM 465 transmission. I don't understand how an exhaust manifold gasket can be installed that far off without it being noticed.

I do notice some exhaust noise somewhere toward the front of the truck, but
I am reluctant to mess with the manifolds because of all the smog tubes which look somewhat fragile to me. I have to keep the smog equipment intact to pass annual emissions in AZ. I just went out and ran the truck and put my hand and a piece of paper near the exhaust manifold in the area you mentioned, but there does not seem to be a leak there. I know idle speed is not a good test, but it seems to be ok. I threw some water on that area and I think what you see may just be a mold mark showing.

I know GM BB exhaust manifolds (as well as Ford 460 manifolds) are prone to cracks, but mine appear to be in good shape, probably due to the dry climate of southern AZ and no rust from salt on the roads.

Thanks to all for the info. When I get the new connector and lead I will give it a go, after I drain out some coolant, since i don't want to have to be quick on the sensor install and risk cross threading it.

06-07-2019, 02:25 PM	#5
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,198	Re: Coolant temp sensor and exhaust manifold gasket interference Yes, I was not thinking about how the engine would be shipped by the rebuild factory. According to the previous owner, a Chevy dealer installed the reman engine and SM 465 transmission. I don't understand how an exhaust manifold gasket can be installed that far off without it being noticed. I do notice some exhaust noise somewhere toward the front of the truck, but I am reluctant to mess with the manifolds because of all the smog tubes which look somewhat fragile to me. I have to keep the smog equipment intact to pass annual emissions in AZ. I just went out and ran the truck and put my hand and a piece of paper near the exhaust manifold in the area you mentioned, but there does not seem to be a leak there. I know idle speed is not a good test, but it seems to be ok. I threw some water on that area and I think what you see may just be a mold mark showing. I know GM BB exhaust manifolds (as well as Ford 460 manifolds) are prone to cracks, but mine appear to be in good shape, probably due to the dry climate of southern AZ and no rust from salt on the roads. Thanks to all for the info. When I get the new connector and lead I will give it a go, after I drain out some coolant, since i don't want to have to be quick on the sensor install and risk cross threading it.