86 running hot after new distributor and ac

[TheLyon32]

First i'd like to say thanks to all who contribute to this site making it a valuable resource for all of us.

I have an 86 (305) that has had temperature issues since I purchased it last november. Upon purchase I replaced the water pump and radiator and everything was good for a few months(ran at 200 deg). I had a new distributor installed and it immediately ran hot(240). My mechanic adusted the timing and everything was good for a month. Then I had my ac repaired and it started up again (220-230).

thermostat has been replaced a couple times.

It slowly creeps up and doesn't run hot until I have been on the highway for about 20 minutes

Any ideas? I just want to get it taken care of and drive with peace of mind not looking at the temp gauge every 10 seconds.

[Irish_Alley]

Can't say for sure but I want to say build up

[Lt.Del]

are you sure it is timed correctly?  imperfect timing can cause overheating.
is your exhaust without blockages? - backpressure will cause overheating.

[beastie_3]

Is it a aftermarket distributor, or a stock replacement?

Triple check the timing, something happened with the swap. Did you change anything else, like spark plugs at the time?

[bake74]

     If it was overheating with the P.O. and he didn't tell you, and since you said you replaced everything external and timmed it right.  I would turn to water jackets inside engine, I know this isn't easy or what anyone wants to hear, but I just took apart a 350 that half of the water jackets were blocked/cacked over with a thin layer of crud.  Maybe check with an engine builder and see what can be checked without a full teardown.
     Hear is a thought, have you done a pressure check on your water system since you replaced all those componets ?

[Irish_Alley]

Don't know why I didn't think of the cats

[1980c10]

It slowly creeps up and doesn't run hot until I have been on the highway for about 20 minutes

based on this alone; your radiator sounds plugged. The other stuff probably has nothing to do with your problem.

when you are at highway speeds your engine is under load and requires more cooling than radiator can handle in its current condition.
 At idle(safely) put you hand on the radiator in differant spots and you should find cold spots.

Get it cleaned out or just buy a new one.

[TexasRed]

It sounded like he bought a new radiator back in November?

[1980c10]

It sounded like he bought a new radiator back in November?

missed that somehow

[TheLyon32]

Installed headers, true duals with h-pipe (no cats), new plugs and wires. All that was before the distributor. That just made the truck sound awesome.

Distributor is aftermarket. Found an ebay link to it here on the site.

Truck has been in timeout for a couple weeks, but I drove it to work today (54 mi roundtrip) and it never got above 200. But its much cooler outside now that it was two weeks ago.

The old radiator was really clogged up, I even see little brown rust flakes in the new antifreeze. maybe residual crud is the issue?
will a flush and fill adrress that? or do I have to find an engine builder?

I've just about reached my limit as far as how much money I'm will to put into this truck....for 2011  .

[topp]

SO you replaced the radiator and never flushed the Cooling system?

[jaredts]

Are you losing antifreeze, even just a small amount?  Is your radiator cap also new?  A cooling system flush would be an easy thing to try.  Have you pulled and inspected the plugs since you owned it?  Any other symptoms like hard start or stumbling at idle or white exhaust smoke?

[TheLyon32]

I didn't do work. I would like to assume my mechanic flushed it, but I have seen worse from mechanics (years ago one guy was supposed to replace my water pump but just filled the system with a bunch of stop-leak). I work 60 plus hrs a week and just don't have time to do this stuff. Plus my mechanic is cheap. installed headers, new plugs/wires, new oil pan, and valve cover gaskets for $300. He even cleaned my valve covers and gave them a fresh coat of black paint.

Got my a/c done for $350 that included r12 conversion,new dryer,evaporator, orfice tube/filters and a used compressor he had lying around the shop


I have replaced the radiator cap.
No hard starts except for having to give it a little gas for about 10 seconds on the first start of the day.
When I inspect the plug what am I looking for?

[jaredts]

When I inspect the plug what am I looking for?

One or two plugs that look different.  Then look at a chart and match it up.  Trying to rule out cracked head, block, blown head gaskets.

[beastie_3]

usually flushing coolant is a job in its own, so if it were done, it should say on the work order.