Still running too hot, Please help!

[ktmrob200]

Ok, here's what all I have done so far: new thermostate (180), new water pump, checked the timing, the radiator is only 3 months old. I have backe flushed, forward flushed, and power flushed. The truck sat for 12yrs. I guess all the junk in the motor has finally started breaking up. Every time I flush it runs within 5-8 degrees of the thermostat for about 10mi. then goes up to 200-210. Also if I drive 60-65 it goes to 210 within a couple of miles. I'm using a Robert Shaw themostat (all brass and copper) not suppose to be altered by rpm. Should I just keep flushing the system or what? Any ideas appreciated, this is wearing me out.<br> Thanks for any help

 

[boatbldr]

You do have your fan shrowd on right? Do both intake and outflow radiator hoses warm up once the thermostat<br>opens? It should be noticable. I don't think you can put your fan on backwards can you? Is the air coming out of the radiator<br>warm? Sounds like you've done all the obvious stuff. I'll keep thinking.<br>Kent<br>

 

[bsaunder]

check your fuel mixture, too lean and it will run hot.

 

[Rustytruck]

You have changed all of the important stuff now for the nitty gritty do you have a fan shroud its needed, Fan, 7 blade rigid works best but some get away with a really good flex fan. runs hotter on the freeway check the carb for being too lean, Check the timimg and distributer advance this is where I suspect problems because your problems are at freeway speeds. dirty system, take a large piece of aluminium window screen and shape it into a Ice cream cone shape about 3 inches long and install it in the top radiator hose pointing twords the front in the end by the radiator. The crap will get caught in there before plugging the radiator. Check and clean this trap every couple of days until it stays clean. Do not leave it in there for too long because it is not strong enough for extended use. after a couple of weeks of dailiy driving most of the crap will be out. New radiator cap with pressure at 16 lbs. recovery bottle so you can fill the system to the top. With an automatic in a warm state divorce the tranny cooler from radiator with a really good tranny cooler. In the engine compartment route as much stuff away from the sides of wheel tubs to aid air flow. Especially heater hose move to top of fender well instead of on the side. Check lower radiator hose for its spring so it doesn't suck flat when hot and at freeway speeds.<br>Give it a shot best of luck<br>Steve

 

[ktmrob200]

Here's where you guys keep confusing me. How do you check the carb for lean? Is this mainly the mixture screws on each side or the the choke thing? I have the timing set at 8 degrees btdc. I don't have any pinging. The reason I feel the radiator isn't flowing that well is when I stop the top area is really hot and the bottom is cool enough to touch. On the ignition advance, how can I check that? Thanks again in advance.

 

[74bronc]

The only way to change the mixture at higher RPM's is to take the carb apart and put bigger jets in it to fatten up the mixture. The idle mixture screws only control mixture at idle and a little above. I would bump the timing up a little to 10-12 degrees. That is where my 302 ran the best. I am guessing that your radiator is the root of the problems here. Have you had it rodded out since you began flushing all the shiznet out of it? I'll keep thinking too!

 

[76Broncofromhell]

Not to undermine your mechanical ability, but did you put the thermostat in backwards? The Spring should be pointing down. If your timing is too high it will run hot as well. I would get an inline flush and take one of the heater hoses off (the lower just sprays too much water) and flush the thing for a good 10 minutes.

 

[67halfcab]

Yep you can put a fan on backwards.<br><br>You can also have a worn flex fan which flattens out and doesn't pull enough air through the radiator and across the engine.

 

[bsaunder]

[quote author=ktmrob200 link=board=5;threadid=8704;start=0#62100 date=1031099337]...when I stop the top area is really hot and the bottom is cool enough to touch. ....<br>[/quote]<br>This is good - the top is hot as that is where the water comes in from the engine, it cools as it flows down and accross the radiator, so the bottom should be cool.

 

[ktmrob200]

Thanks to all for the replies. I just got the radiator back from being rodded out, the guy said it was not that dirty. I'll be putting it back in today and let you know how it goes. Thanks again<br> Rob

 

[WyleCoyote]

Just another thought, are you using the stock temp gauge, or do you have an aftermarket? I personally don't trust my stock gauges that much..

 

[Rustytruck]

Fill the truck up with water and keep the cap off start the truck until it is at a stable temp. steal your moms kitchen thermometer that she uses for roasts and stick it in the water. check the temp against the guage you are using. Clean thermometer very well and give your mom a kiss. temps should be close within 10 degrees or so. If your truck isnt boiling over you havn't reached 230 yet.

 

[ktmrob200]

Well all seems well, according to my stk gauge and thermometer she's not going over 190-195 at speed or stop. Going to get a temp. gauge just for piece of mind.<br>Might also try a 10" pusher fan for wheelin'.<br> Thanks again

 

[J-DUB]

[quote author=rusty truck link=board=5;threadid=8704;start=0#62967 date=1031343590] steal your moms kitchen thermometer that she uses for roasts and stick it in the water. check the temp against the guage you are using. Clean thermometer very well and give your mom a kiss. [/quote]<br><br>That's some funny Shoot!!!

 

[rulebreaker]

Make sure your engine draws fresh outside air not air from the engine compartment. This makes a big difference

 

[67_super_sport]

I run a 160 degree thurmistat and mine stays right around 180 winter or summer parked or highway.

 

[mlogan24]

Don't know how relevant this might be, but I finally just got mine running cool-actually too cool now. I have a rebuilt serp. water pump, 160 (was 195 like is stock in the 5.8's, but I had changed it on the off chance it was my heating culprit), and stock 3 row V8 rad. I had a cooling prob, but it turned out I had a standard rotation fan on (I was driving around for a year with a big turbulence machine attached to my engine basically). Now with the reverse rotation fan I can't get over 165 (even in 100 deg. weather) so I'll be going back to a 180. Moral of the story for this thread-a reverse rotation pump, appropriate fan, and no shroud actually seem to work (although I still want to add a shroud to better cool the block itself). Hope that helps.

 

[ktmrob200]

Well, I have to tell you guys what I have found to be the real source of my heating problem. After the rad. was cleaned, it was running cooler. I installed new gauge, but was still getting up to s little over 200 when driving highway speed. I saw a post by howiebuilt about vapor lock saying to to put in a fuel filter with a split and run the small side back to the tank. I did this, but left my clear filter between the new one and the carb. Now the clear one always has gas and temp. at 65 and up hasn't risen above 190.<br> I just have to say I really love this forum.