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Like many diagnostic processes, you have to follow all the steps and not skip the ones you don’t like.
If you are just feeding her some drinks, feeling her up, and then checking to see if she is damp you have to slow down. No wonder you’ve got problems.
Everyone made some great points, particularly about the seeing if you have coolant flow.
I wold start by trying to bleed the system seeing as you have serviced the cooling system recently. Alot of cooling system issues are due to air in the system.
How to bleed a cooling system –
http://www.youtube.com/watch?v=zUpXgAJ1 … ure=relmfu
Next i would be checking the operation of your radiator fan as well as checking for debris around the radiator.
I would remove a few spark plugs and see if there is evidence of coolant being burned during the combustion process.
Out of curiosity, why are you running that temperature thermostat?
The first thing to do would be to check the spark plugs.
I realize you may be using that T-stat as a band aid for something, but it can cause new problems. What is the stock T-stat? 195?
If you have a short commute, that T-stat could be a disaster and I think you would see evidence of a rich mixture on your plugs.
If you have actually achieved high flow with that water pump and 150 T-stat ( a big if) you have a condition that causes blown head gaskets in some engines.
I don’t know exactly what effects those mods would have in your vehicle, but there’s no substitute for a properly functioning cooling system.
I hope you do not take offense. I was a DIY wrench turner until I was 27 and know a lot about mistakes because I made them myself, usually because somebody older and with more experience gave me the wrong advice.I would say the overflow has a hole. I will start by looking into the overflow, just before going into the hard difficult stuff.
Quoted From yarddog1950:
The first thing to do would be to check the spark plugs.
I realize you may be using that T-stat as a band aid for something, but it can cause new problems. What is the stock T-stat? 195?
If you have a short commute, that T-stat could be a disaster and I think you would see evidence of a rich mixture on your plugs.
If you have actually achieved high flow with that water pump and 150 T-stat ( a big if) you have a condition that causes blown head gaskets in some engines.
I don’t know exactly what effects those mods would have in your vehicle, but there’s no substitute for a properly functioning cooling system.
I hope you do not take offense. I was a DIY wrench turner until I was 27 and know a lot about mistakes because I made them myself, usually because somebody older and with more experience gave me the wrong advice.I missed the part about the 150 t-stat. I was taught that the old wives’ tale about leaving out a thermostat (or in this case using one that will basically be always open) to fix an overheat could actually cause an overheat, because the coolant is flowing all the time and the radiator may not have time to properly displace the heat from the water. I would start by going back to the stock thermostat to begin with. If the scenario I described is going on, you could be boiling coolant off slowly… I think… Why did you switch to that t-stat out of curiousity?
Well, lets look at what you have. The cooling system is holding pressure, so you probably don’t have any leaks. You add coolant to the overflow tank, and it disappears. Also, the radiator is a hair low when you checked it. If it sounds like I’m typing my thoughts, I am. I’m wondering where the coolant is going. You must be losing it somewhere internally if it is emptying the overflow tank and is still a bit low in the rad itself. You may have a slight head gasket leak, because I can’t think of anywhere else for the coolant to go if it’s not leaking externally. No puddles at all under the truck? I would rent a block tester and make sure you don’t have exhaust gases in the coolant. Or buy one. I priced ’em out, around ~$45. I had a ’95 Taurus that slowly used coolant (about a gallon total every couple months). I’m fairly certain it had a head gasket leak, although I never tested for one, as I was content to add coolant on occasion. Long story short, the truck is using coolant from the overflow and then the rad when the overflow runs dry. It’s odd that your pressure test holds at 18 psi, but I can’t think of any other explanation. Did you find a good long block to swap into this truck yet?
You’re a great brother for driving him so far to school everyday.
As for the coolant, is there good flow when the truck is at temperature?
Hi Beefy, I had an MGB in the early 1970s and moved to southern CA. It seemed to run too hot. Some “expert” told me to take the T-stat out. It did run cooler for some weeks of short trips, then I drove it for some distance and it blew a head gasket.
Ok [b]AccordinGB made no since to me…. As I stated iv been watching this problem for some time trying to figure it out…. And its not even a problem its more like one of those weird things that just happen. I follow steps and watch for things on my truck like you read. well i cant say read bc apparently you cant do that very well seeing how you messed the part where i stated iv been looking into this issue every what way i can. Im aware of the fact i may have a problem. I dont need you to tell me that seeing how im here asking how and why.
+1 to beefy on the block test idea…. I have already ran two or three block test on the engine and do not have any [/b]exhaust gas in the system.
Iv been watching the system like i said and the radiator never drops below a cup. You can pop the cap off and always see water. Its just the overflow that loses the water.
Iv got a buddy who has a road simulator/dyno Ill talk to him and see if there some way to use it to find the problem.
The more and more i think about it The overflow has to be leaking bc the radiator does drop in lvl.
Yarddog Thanks for the advice. Iv done alot of work on these 5.0/302s these older engines love to run cold. I try to keep mine between 160 – 180.
I agree with you on the cooler stat making the engine run richer. That is 100% true and part of the reason I run them. YES it kills gas mileage but idc.
The pcm (computer receives info from the engine then the pcm tells the ejectors/ fuel system how much fuel to spend at different temps =Lower temps = more fuel = 1.00% more hp – fuel mileage. As for hurting them i cant be sure… IM sure it could on some of the new engines.
sorry it is a 160 stat. my bad. I put the lower stat in bc we have really high temps here (110+) and i make alote of trips to NM so temps are something i keep a eye on.Iv only seen one car that ran better the hotter it got and that was the 455 rocket in my dads 71 oldsmobile cutlass the hotter see got the better she ran.
As for your mgb running hot – it makes me wonder if you did not already have a blown head gasket and then removing the stat made it worse.
This would happen bc – The lower part of the engine is hot the upper part is trying to heat but cant reach a good operating temps due to the constant flow of water. Almost works the same way when u put cold water in a hot engine = it cools to fast.
The same as what beefy said!!!I agree 100% about never running a engine with out a stat. WELL most engines. Alot of race car engines dont use any stat but thats different.
+one on the spark plugs idea – Iv got a set of Bosch super coppers iv been wanting to put in…Will do asap.
Thanks guy!
BTW iv also got a 4core radiator system.
Iv also got a oil cooler on the truck. Anyone think there something along those lines that could mess with it???My buddy owe me alot of money. He just got rear-ended the other day and killed his 351 HO mustang. Well I can think of ways he can start paying me back lol!!!
I would remove the overflow and seal off any flow points and put a dyed liquid in it, and see if any leaks are present. This may take a while, but it may be such a small leak that the coolant does not make a very prominent leak spot. Only by removing the overflow can some leaks be seen sometimes. If you cannot see that any leaks are coming from the overflow itself, or any coolant lines (inspect after they are clean to be able to see if any change happened) then like all the other posts, the leak would be internal.
Are you thinking about dropping that 351 in your truck? lol
That would be awesome.
I would check the over flow real good for leaks.
Do you have hose clamps on the hose that goes to the over flow to the rad?
I’ve had cars lose coolant like that and putting good clamps on both ends of the hose fixed it.
Quoted From OnThe7ThDayFord:
Ok [b]AccordinGB made no since to me…. As I stated iv been watching this problem for some time trying to figure it out…. And its not even a problem its more like one of those weird things that just happen. I follow steps and watch for things on my truck like you read. well i cant say read bc apparently you cant do that very well seeing how you messed the part where i stated iv been looking into this issue every what way i can. Im aware of the fact i may have a problem. I dont need you to tell me that seeing how im here asking how and why.
+1 to beefy on the block test idea…. I have already ran two or three block test on the engine and do not have any [/b]exhaust gas in the system.
Iv been watching the system like i said and the radiator never drops below a cup. You can pop the cap off and always see water. Its just the overflow that loses the water.
Iv got a buddy who has a road simulator/dyno Ill talk to him and see if there some way to use it to find the problem.
The more and more i think about it The overflow has to be leaking bc the radiator does drop in lvl.
Yarddog Thanks for the advice. Iv done alot of work on these 5.0/302s these older engines love to run cold. I try to keep mine between 160 – 180.
I agree with you on the cooler stat making the engine run richer. That is 100% true and part of the reason I run them. YES it kills gas mileage but idc.
The pcm (computer receives info from the engine then the pcm tells the ejectors/ fuel system how much fuel to spend at different temps =Lower temps = more fuel = 1.00% more hp – fuel mileage. As for hurting them i cant be sure… IM sure it could on some of the new engines.
sorry it is a 160 stat. my bad. I put the lower stat in bc we have really high temps here (110+) and i make alote of trips to NM so temps are something i keep a eye on.Iv only seen one car that ran better the hotter it got and that was the 455 rocket in my dads 71 oldsmobile cutlass the hotter see got the better she ran.
As for your mgb running hot – it makes me wonder if you did not already have a blown head gasket and then removing the stat made it worse.
This would happen bc – The lower part of the engine is hot the upper part is trying to heat but cant reach a good operating temps due to the constant flow of water. Almost works the same way when u put cold water in a hot engine = it cools to fast.
The same as what beefy said!!!I agree 100% about never running a engine with out a stat. WELL most engines. Alot of race car engines dont use any stat but thats different.
+one on the spark plugs idea – Iv got a set of Bosch super coppers iv been wanting to put in…Will do asap.
Thanks guy!
BTW iv also got a 4core radiator system.
Iv also got a oil cooler on the truck. Anyone think there something along those lines that could mess with it???My buddy owe me alot of money. He just got rear-ended the other day and killed his 351 HO mustang. Well I can think of ways he can start paying me back lol!!!
+1. and definitely agree, those 302s love to run a little cooler.
ive actually had an expierience in which coolant was only being lost while driven and not at idle. as you probably agree, the overflow to radiator hose isnt attatched with very much. it was actually pushing coolant out of where the line connects. i dont know why it only did it when driving it, but its something to consider.
If the overflow tank was leaking, you would have puddles under the truck. For kicks, fill it up all the way with water and check it for leaks. Make sure you have a plan to get the water back out. Also, I agree with the above post to check the hose from the rad to the overflow and it’s connections.
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