having a cooling issue that's driving me batty. I'm running a circa 1988 chevy 350, mild cam, efi, stock heads, novak aluminum rad w/ 3 spal e fans in my 88 XJ. Everything was working fine earlier this year -- rock crawling at rausche creek, zero overheating, driving at normal speeds on the highway, no issue. I grenade my d35 over the summer, replaced that with a f8.8, and since then, have had nothing but headaches with overheating. I'm sure one has nothing to do with the other --- only mention it because it was sitting around for a few weeks in a shop, not being driven. The day I get it back, it overheats on the drive home. This is driving me crazy. At idle, it sheds heat with no problem. But if I go over 2200 rpm or so, regardless of how fast I'm going, heat starts slowly climbing. At rausche creek two weeks ago, no issues with low idle crawling, but heading back on a long uphill access road, hit 230 before I had to pull over.
I'm at the point where I think I may have a blown head gasket (I'm going to do a compression test when I get back this week), but anything else on the "idiot" checklist I missed? This is what I've done:
I'm at the point where I think I may have a blown head gasket (I'm going to do a compression test when I get back this week), but anything else on the "idiot" checklist I missed? This is what I've done:
- confirmed tstat was working properly and in the right orientation. tried a 160 degree tstat, no difference. Tried running with no tstat, no difference
- lower rad hose looked snarky, thought maybe it was collapsing. replaced, no difference.
- checked timing -- running 12 degrees initial timing, 34 degrees total timing (timing was retarded --26 degrees total timing). no difference
- Replaced water pump. Tried a stock replacement from advanced auto and a high-flow from edlebrock. Confirmed both were reverse rotation pumps. No difference.
- Raised a/f ratio at cruise to 13.8. No difference.
- changed icm (I know, but I figured what the hell)
- confirmed all fans are working. Set them to turn on at 180.
- changed tensioner and serpentine belt (it was late and I ran out of ideas)
- pulled winch, lights, and everything else from the front of the truck. Thought this may be impeding air flow. No difference