Hi All.
Just finished up the head gasket replacement. Everything running nice. Just been having trouble with cooling. I'm using an ultra gauge. I just replaced the thermostat with a soft spring 180 which did seem to improve the situation. Plus pressure testing the system I managed to find a small leak from the upper radiator hose. Clamp needed re positioning and tightening. All seemed good, careful bleeding of the cooling system and it was still getting too warm. The cooling fan kicked on at around 205 I think it was. Got to 210 and I switched off. What I noticed was that the temps on the radiator varied a lot. Upper left was quite warm, where as moving toward to right and lower almost still cold. That sounds like a clogged radiator to me. I replaced this probably around 10 years ago. Since that time the car was not driven a great deal. Is that something that's normal from low use? Also while under pressure test I checked all around heater core and feed hoses. No leaks there at all.
Cheers John.

 

Hey there

I went through this a few months ago. In my situation I replaced a cracked radiator but still had overheating issues.

I went down a rabbit hole of bleeding air from the coolant, installing a severe duty fan clutch( after checking the old one was bad), and finally I removed the new 180F thermostat.

I tested the thermostat in a pot of water on the stove and found the new stat wouldnt open until the water was above boiling temperature.

I replaced with a genuine thermostat and it solved my issues.

Perhaps check the thermostat and fan before buying a new radiator immediately, but i also noticed there were some temperature differences across the new radiator.

After all of the above my truck ran at 194 in ambient temps of 80 F

 

If one section of your radiator is significantly cooler than another after the vehicle gets up to operating temp, yeah, it sounds like a clog. What can cause a clog? Almost anything, but small bits of corroded metal could certainly be the culprit. The radiator passages are not all that large.

Sometimes a reverse flush will work to clear the passages. Other times, not. It is difficult to say. A new radiator isn't terribly expensive, but like many 'new' things these days, quality/durability can be a concern.

 

Yeah, I agree. I would hope to get more than 10 years out of a rad though. Presumably you diluted your anti freeze with distilled, not tap water (but I think your water would have to be quite hard if it were to clog it up in 10 years). Also, if there was ever any Stop Leak product in your system that didn't get flushed out. Mixing antifreeze types can cause it to gel up (Mixing brands is okay, but it needs to be the same type). I don't have experience with Dexcool, or similar antifreeze types, but I think it can gel up over time, especially if it gets mixed with other types.
My $.02

 

I always used distilled water. It may have been more than 10 years. Would you think flushing the radiator could help? I read here somewhere they don't flush very well. Another thing I forgot to mention. Before I fitted the thermostat I noticed the aux fan did not come on? With the new one it now kicks on at around 205. So I'm getting things moving better. Maybe before I buy one I'll try the flushing and bleed again.
Cheers John

 

From what you're saying I'd be more suspicious of a bad thermostat (even if it's new) than a bad radiator.

 

Have you read this? https://landroverforums.com/forum/di...thread-105010/ or this? https://landroverforums.com/forum/di...-truck-126823/

 

I took a little break from the disco I'm back on it now. I have read through the links. One question I do have is in regards to the multigauge ( I think that's the name) that I'm using to monitor engine temp as the stock one is apparently not to be trusted. I'm getting very conflicting readings. When the gauge is telling me I'm getting up to 220 and the aux fan has kicked on. I use the IR temp gun to take various readings across the engine. Hoses, radiator, base of temp sender, unit behind alternator and the cylinder heads themselves, everything is completely normal? For instance at the temp sender unit base I get 170? Could the sender unit be faulty and sending incorrect info to the obd port? Have you heard of this happening? I just did the Head Gaskets and want to make 100% sure everything is good.
Thanks for your help.
Cheers John.

 

Yes , could be your sensor, they do go bad. Checking with the ir gun was the right move.

 

Thank you. I'll get one in there and let you know.
Cheers John