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Nigel
06-02-05, 08:44 AM
I have a cobra with a chevy 350 , 5.7 engine, can anyone advise what temp should/normally run at. I expect it to rise when stood/in traffic etc but has been gradually going up to 120 mark when running. Temp resolved by removing thermostat which is ok but not getting to proper running temp. I ve been told 120 is normal temp for a chevy yet others say is too hot. Not seen any steam or bubbling and runs ok. Bought a new thermostat as old one was US but made no difference. Tried new temp sensor unit and new resistor to temp gauge and no difference. Want to make sure is ok for the red hot summer this year and before driving to Le Mans in June. Any ideas, suggestions, is this a problem or not? Thanks, Nigel.

gd02 cob
06-02-05, 10:52 AM
This time of the year mine runs at 175-180 F which is a true temp via mechanical gauge. Stationary it will rise to perhaps 185F then the fan will operate.

It may increase slightly in the summer in both situations, but not dramatically.

Both these relate to Water temps.

Nick

plod
06-02-05, 02:35 PM
Mine tends to run at around 70c I think.. or somwhere just shy of half way round the gauge..

Best I can do. Have you flushed your system through?

Paul

Miket
06-02-05, 03:02 PM
Normal running on mine 85C to 90C = 185F to 194F

Fans click in at 90C

andywsussex
06-02-05, 07:22 PM
Nigel,

Mine runs at about 90C (water) when driving. Thermostat opens at 82C (from RePower). Fans are adjustable, have mine kick in about 95C. Oil temp. gets to about 90C as well, though takes a long time to get up to temp, and doesn't reach that if I'm on the motorway doing a good speed.

If it stays cool without the thermostat I'd suspect either the 'stat or the radiator's performance. Have you got the thermostat the right way round? Tried the usual test in a pan of water? Is the radiator relatively new and of sufficient size and capacity for the engine? Any chance its got gummed up with something?

Of course, the alternative is that the gauge isn't working. My expansion tank (standard Dax) pressure relief valve blows at around 120C. I know all engines will vary as to what pressure 120C equates to, but I'd have thought they'd all be pretty close. I would think that if it were really at 120C when driving, the moment you stop the temp would rise sufficiently to blow the valve before the fans have a chance to cool it. I take it this isn't happening?

Andy

Nigel
08-02-05, 06:06 PM
Thanks for the replies, fitted a brand new thermostat last night and pressure cap, I think the right way round looking at the box, and new pressure cap, ran her for a couple of minutes, went round the block and staright upto 120 degrees c. Fans didnt kick in though which usually do!

Will re fit at weekend and see if any obstructions in housing. Will also flush system and use some cleaner I have bought. Seems strange that as soon as thermostat goes in it starts playing up. Dont think its the dial.

Will also check top and bottom hoses to see if both getting warm. Best. Nigel

Andy S
08-02-05, 07:21 PM
Nigel I've got a small block Chevy in my Southern Roadcraft and she runs at a constant 85 degrees, rising to 90 in traffic, fans come in about 87-88 degrees.

Mr Bling
08-02-05, 08:48 PM
Nigel
My Ak runs around 90 and fan set to cut in at around 95. Mine was running hot just under 100 so i fitted an oil cooler - its been fine since then. Have you got a radical cam in your chevy or something? 120 seems too high for comfort? I would suspect the gauge or sender unit in the block as well
Good Luck
James

Miket
08-02-05, 09:47 PM
Fans didnt kick in though which usually do! Nigel if my fans didn't kick in at 90 my temp would go of the clock, I would check your fans first. :( :(

kdavies3
08-02-05, 10:00 PM
Hi Nigel, are you running an electical gauge if so they are notoriously unaccurate.
they can be calibrated through the small access holes in the back this is assuming you have smiths style gauges.

Andy302
09-02-05, 05:43 AM
Thanks for the replies, fitted a brand new thermostat last night and pressure cap, I think the right way round looking at the box, and new pressure cap, ran her for a couple of minutes, went round the block and staright upto 120 degrees c. Fans didnt kick in though which usually do!

Will re fit at weekend and see if any obstructions in housing. Will also flush system and use some cleaner I have bought. Seems strange that as soon as thermostat goes in it starts playing up. Dont think its the dial.

Will also check top and bottom hoses to see if both getting warm. Best. NigelNot actually running a V8 yet so I cant say how quick they would normally warm up but a couple of minutes running and then a trip "round the block" seems a bit short to hit 120C, of course I might be wrong and thats normal! is the gauge OK? Try emailing the manuf. to see if there are any tests you can perform, you know the sort of unplug the sender and measure resistance accross the harness etc. Also do the senders have to be matched to the guage, i.e is the guage missinterpreting the sender output due to a spec. difference?

Of course if its worked in the past then my last comment isnt so applicable.

Cheers

Nigel
09-02-05, 06:50 PM
Hi, I have an oil cooler fitted and the cam is normal as far as Im aware, nothing special, I tried a new temp sender unit and have got a spare gauge I am going to try at the weekend if I can get past all the wires and other gauges behind the dash. Previously the fan s have come in and Im starting to suspect its not as hot as it shows, just cant understand why it starts this as soon as the thermostat goes back in, I have now fitted two new ones, both tested and working. Draini g the radiator at weekend also...will keep you posted, Nigel.