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Discussion Starter · #1 · (Edited)
ive had my truck running for about 12 mins at a guess
the temp gauge reads 92 and the pipes seem to be under pressure
there is no fan connected to the water pump pulley at the moment

do i have issues with the possibility of a head gasket issue of is this normal for that amount of running time
engine is a 305 small block chevy 1990
thanks
 

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I'm Not Jed Clampett
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Sorry to answer a question with more questions, but a bit more information would help.

Is your temp gauge sensor in the stock position in the cylinder head?
Does the rad feel really hot, fairly hot, or coolish when you get the 92 degree reading?
Do you still have the stock thermostat installed?
 

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Discussion Starter · #5 · (Edited)
thanks for helping mate
ok the temp sensor is in the radiator
yes its far too hot to touch
i think it does have the std thermostat still installed
i do have 1 of these spare if you think i should install it

the metal fan would be 35mm from the radiator
i do have a 14"fan mounted 10mm from the rad on the other side controlled by a adjustable temp switch and a override in the cab

thanks
 

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I'm Not Jed Clampett
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The std thermostat in a late motor is quite likely to be 85 degrees C or thereabouts, so when the water does hit the rad it is going to be hot, with no engine driven fan it's going to get hotter when the truck is standing still; I wouldn't worry unless the electric fan doesn't knock the temperature back when it does cut in..
 

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Discussion Starter · #7 ·
i can't fit that fan as it will hit the bottom rad hose
should i loose the stat i don't have a heater in the truck
ill remove the rad and see if i can get the elec fan right up against the radiator
just after seeing all those motors yesterday overheating I'm a bit paranoid
 

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Keep the stat. If you remove it all it does is make the engine take longer to get up to temp as you're heating the water in the rad as well as the engine. It will still get hot, just take longer.

Why is the temp sender in the rad? Until the stat opens you won't get a true temp reading.

The rad feels hot because it is hot! The water hitting it is at 85 degrees, your body temp is 37. I have always found that the rad hoses feel hard when the engine is hot. They're pumping water under pressure. Are they soft when the engine is stone cold, even when running initially?
 

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I'm Not Jed Clampett
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Personally I wouldn't rush to remove the stat, if you really want to, just cut out the centre section, and leave the rest in place; you need some restriction to make the the water circuit work correctly.

Running with a stat shouldn't be problem as long as you have enough cooling capacity, you would get better engine power (if that's important to you) by changing to a 70 degree stat.

Not having an engine driven fan isn't a problem as long as your charging system produces enough power for a decent electric fan; I have a 16" fan in front of the rad in my truck, you can almost see the needle move on the temp guage when it cuts in, but it does take 20A running and nearly 30A on cut in, so it's well worth having a relay in the thermostatic switch circuitry if you have a big fan.
 

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Discussion Starter · #11 ·
ok I've put the cooling fan straight on the rad and yes it runs through a 30a fused relay
from cold it takes 9 mins for the stat to open then the temp reads 75degrees and unfortunately at 80 i turned the fan on only to watch it go up to 105 over the next 8 mins

where should the temp sensor be located
 

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Discussion Starter · #13 ·
i will read this tonight kev when i have time to read it properly and understand it
thank you



i have got a adjustable fan switch that needs to be in contact with the radiator to be able to read the temp correctly
i thought about using a copper tube up against the top part of the rad with the sensor in side it
can i araldite the tube to the top of the rad or must i use low melting solder

no kev i have not bled the system as i don't really have a system to bleed all i have is 2 hoses to the radiator

yes the water only just toughed the top of the fins to allow the top part of the rad for expansion

thanks for the help guys

id like to get the fan switch set up correctly then re test the system
at what temp on the radiator should the fan cut in at
thanks so much for all the help guys
 

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could the rad be silted up/ blocked? sure it should get hot but the air coming out the back should be hot too or the rad isn't doing its job...
as the stat only maintains the temp in the block (when the stats work properly) so the top hose will be hot but the lower hose should be considerably cooler ..or the rads not cooling enough...
i have a vette- completely stock '77 manual..that even in saudi 50 degree C heat kept cool.. it has the stock factory fan mind...they put it there for a reason(viscous coupling type)
neil
 

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Discussion Starter · #15 ·
the rad is brand new alloy unit from charlie chop on here
so i assume its up to the job of cooling the engine

i can't use a fan unless i cut it down as it will hit the bottom rad pipe
 

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Discussion Starter · #17 ·
plenty of room for air to move around .its a small engine in a big hole
my neighbour is in the garden so thats stopped play as i don't want to be getting complaints about the noise on the truck



as per earlier post
can someone tell me where the temp sensor should be located
 
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