Engine runs hot

[Darth Plasma]

My '87 TBI 350 constantly runs at 210 degrees F, no more, no less. It heats up fast when cold. It likes to push 260 at high speeds going up hills, and at idle it slowly slowly raises past 210. It has a single aftermarket electric fan. The radiator looks stock and it has a slight weep below the overflow line. All that's in front of it is a battered trans cooler, i removed the AC. truck has a new AC Delco 195 thermostat and brand new coolant in it. Could it be the water pump? Even with the electric fan going at idle from first starting up it shoots to 210 in a matter of minutes and itll slowly creep past it within 10-15 mins. Any ideas?

 

[Darth Plasma]

Oh and when it reaches like 230-240 it'll throw a service engine soon light and the truck instantly runs way rich and bogs down, and the code is just a continuous blinking

 

[Shorty81]

If your water pump was bad it would be weeping out of the check hole. Your radiator and system probably needs flushed. Also maybe not enough air flow. What's your timing set at? Do you have a shroud ??

 

[Arkansas_V8]

Timing will cause it to heat quick.

CTS sounds like the other issue.

Just guesses from a redneck.(my excuse for everything)

 

[Arkansas_V8]

I run two electric fans, and even on the most humid and hot day I only turn them on if I sit for a bit. I run a super huge radiator, see I cut the holds to hold it down.

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Serious about the timing. It happened on my other tbi. Set it great by ear, but it ran hot real fast on a short trip, not a catastrophic hot, but much higher than it should.

 

[Darth Plasma]

I replaced both CT sensors with the thermostat, I did check the timing a long time ago and it looked about right but I should check it again. Never thought about the timing. I’m gonna upgrade to a bigger radiator soon

 

[Darth Plasma]

If your water pump was bad it would be weeping out of the check hole. Your radiator and system probably needs flushed. Also maybe not enough air flow. What's your timing set at? Do you have a shroud ??

I’m gonna check the timing again but last I checked it was 0 as it should, there is no fan shroud, and just a battered old trans cooler in front of it

 

[Arkansas_V8]

I’m gonna check the timing again but last I checked it was 0 as it should, there is no fan shroud, and just a battered old trans cooler in front of it

No shroud would make it warmer than with one, but I have never seen it that bad.

Mine likes about 8-10 btdc. Just play with it a bit.

I just dont think timing alone would cause both your issues. Keep updating. I have already admitted I am from the south(meaning I am slow). Need a bit to think about it.

Unless you aren't experiencing a rich condition, but Vapor lock. Then timing may explain both.

I would also flush it all out, change the waterpump if its old anyway(may be weak). Not a ton it could be.

Air in the system.

Head gasket putting exhaust in the system, that would build pressure and shove it out the overflow, or cap if thats weak.

Its a SBC, not alot to go wrong.

 

[Darth Plasma]

No shroud would make it warmer than with one, but I have never seen it that bad.

Mine likes about 8-10 btdc. Just play with it a bit.

I just dont think timing alone would cause both your issues. Keep updating. I have already admitted I am from the south(meaning I am slow). Need a bit to think about it.

Unless you aren't experiencing a rich condition, but Vapor lock. Then timing may explain both.

I would also flush it all out, change the waterpump if its old anyway(may be weak). Not a ton it could be.

Air in the system.

Head gasket putting exhaust in the system, that would build pressure and shove it out the overflow, or cap if thats weak.

Its a SBC, not alot to go wrong.

Pretty sure the water pump is original. I’m gonna eventually replace the head gaskets but they don’t seem to be causing an issue

 

[Arkansas_V8]

Pretty sure the water pump is original. I’m gonna eventually replace the head gaskets but they don’t seem to be causing an issue

I would replace water pump for sure then. I was just throwing ideas out. Boredom. Hope you get it figured out.

Oh, dont forget to triple check the timing.

 

[4WDKC]

either your electric fan isnt moving enough air, its wired backwards or you have a serious issue.. I had a 93 gmc with the the v6 that had a coolant leak i didnt know about, after 30 min sitting in traffic without the fan coming on it was almost into the red. Once I got moving it cooled down to normal temp so I could get home. Your radiator maybe plugged and need to be cleaned or replaced.

 

[donnieray]

I'll throw my two cents in, a thirty plus year old radiator is most certainly clogged. And you do need a shroud. My 84 and 86 both had original radiators and both were clogged as hell. I found good aluminum three row units at a good price and fixed two trucks. If your truck has a fan clutch check that.

 

[Arkansas_V8]

I'll throw my two cents in, a thirty plus year old radiator is most certainly clogged. And you do need a shroud. My 84 and 86 both had original radiators and both were clogged as hell. I found good aluminum three row units at a good price and fixed two trucks. If your truck has a fan clutch check that.

He has a single electric fan. Radiator I agree.

I would hope someone with an overheating problem like this, would run a hose through the radiator, see if its clogged.

Like I said earlier see if he cant flush it all out.

 

[donnieray]

He has a single electric fan. Radiator I agree.

For some reason I was thinking the single electric fan was added with the stock fan in place. I've seen that a lot.

 

[Arkansas_V8]

For some reason I was thinking the single electric fan was added with the stock fan in place. I've seen that a lot.

I have just always went straight to electric.