Overheating - what do i check?

[Hoot]

Sorry to repost in a new thread but i think i have a different issue at work here which warranted a new title.

hey guys i replaced my expansion tank on sunday and got rid of my wanky brass radiator bleeder plug and put back in a stock plastic one. I bled the system and refilled the coolant. I drive it out on a road trip up the coast of CA to pt. reyes drove it up and down the steep hilly northern california terrain with my wife in the passenger seat and the AC going the whole time. I had no problems. the heat guage sat right where it should the whole time.

today coming back from an interview my rover started overheating bad on the way home. i live in the oakland hills so there is about a 3 mile steep climb up hill back to my house. it was all the way to the red by the time i noticed it. DAMN!!

what the hell is causing it to overheat now? what;s the next thing for me to check? there are no coolant leaks anywhere. after the rover cooled down i checked the expansion tank and it was full to the fill line, right where it should be.

Whats the next move for me to make? what is the likely culprit? what is the process i take to track down my issue?

any help will be appreciated.
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[nosivad_bor]

take it to a rad shop and have them check it out. probably cloged in some way.
why did you put the plastic cap back on??

 

[scottjal]

Were you in traffic today verses the test drive being mostly open roads above 30mph? That's probabbly a fan clutch not engaging issue?

Otherwise looking at the radiator?

 

[Hoot]

i put the plastic cap back on because the brass one started corroding and it was really hard for me to get it off. i had to pry on it so hard that the top of the radiator started to bend a bit. so i opted for not going through that again and went with a nice new plastic one.

the rover actually didn't over head in the stop and go traffic. it overheated on the steep incline drive home, three miles uphill through winding paved mountain style roads.

i jsut took it out and drove it around througfh the neightborhood with the AC on full going up hills and pushing it hard, basically driving like an ass and it di dnot over heat at all the needle stayed dead center. i parked it in the drive way and checked all the fans the two electric fans that kick on with the AC were both going full blast. i turned off the Ac and they shut off. i checked the radiator fan attached to the delighful fan cliuutch and it was going full i took out my lisly stethoscope and listened to the ac motor and the water pump and they both sounds nice and smooth humming away.

what can it be otherwise? is there a better way to check the water pump and the fan clutch?

is it just my radiator? how much is a new rad gonna cost me. my wife and i both just quit our jobs and are trying to work as independant contractors so money right now is reallll tight.

again, all your help is appreciated.

 

[Hoot]

i may be a numb nuts but i may have added to rich a coolant to water mix. meaning i may have a 90 percent coolant to 10 percent water mix in there. would that cause the system to overheat when it gets really hot out? becuase it has only occured when it is really hot out. needless to say i will be draining my whole coolant system before i drive it again.

any recomendations on a coolant flush or what type of coolant i should put back in?

 

[vabiro]

i put the plastic cap back on because the brass one started corroding and it was really hard for me to get it off. i had to pry on it so hard that the top of the radiator started to bend a bit. so i opted for not going through that again and went with a nice new plastic one.

You might want to try some plumber's tape on threads. The problem with the plastic is that they break level with the top of the rad, leaving the threaded piece stuck in the rad. This has happened to a number of people I know (me included) who tightened the plastic cap too much.

the rover actually didn't over head in the stop and go traffic. it overheated on the steep incline drive home, three miles uphill through winding paved mountain style roads.

I had problems with mine overheating only when the air was on and speed was 40mph or more, or on the highway doing 70+ without the AC.

It turned out the rad was full of mud and crap. Try spraying it out from the inside outward. It took about 20 minutes with the rad out and on the ground, using a garden hose, before the water started to run clear. Now all the problems are solved.

That is all it was after I had replaced the thermostat, coolant, viscous fan clutch, water pump, tensioner. All it took was about an hour or two to remove the rad and spray it down.

what can it be otherwise? is there a better way to check the water pump and the fan clutch?

is it just my radiator? how much is a new rad gonna cost me. my wife and i both just quit our jobs and are trying to work as independant contractors so money right now is reallll tight.

again, all your help is appreciated.

Someone suggested that a shop rag should stick to the front of the grille when the engine is reving at about 2k rpm and the fan clutch is working.

Don't run out and buy a new rad. They are something like C$1200 here in Canada, and even knock-off stuff from Rover;s North is going to cost ~US$600.

There could be:
- an obstruction in the rad
- bad coolant mixture
- air in the cooling system (can you hear bubbling in the heater core)
- low coolant level (it should be at the level indicator when cool)

Cheers
Victor

 

[vabiro]

i may be a numb nuts but i may have added to rich a coolant to water mix. meaning i may have a 90 percent coolant to 10 percent water mix in there. would that cause the system to overheat when it gets really hot out? becuase it has only occured when it is really hot out. needless to say i will be draining my whole coolant system before i drive it again.

any recomendations on a coolant flush or what type of coolant i should put back in?

Definitely could cause problems. The tool for testing coolant mixture is about $5 and worth having in the tool box.

It should be 50/50 most of the time. Premix is often the best, except in extreme heat or cold.


Victor

 

[rmuller]

Do you do deep water crossings? I overheat when I get a ton of mud stuck in the radiator.. I just pull off the plastic shroud on top, and get a hose (low pressure) and clean the mud out..

Just a hint incase you didnt know: When you are on the road/trail and you overheat, throw the heat on full blast (more comfortable if you put it on Floor only), and it'll return to normal and you wont damage anything...

 

[deiaggie]

mine would get hot when it was very hot outside, I thought it was the fan, so I bought a new Hayden fan and it pulled more air and seemed to cure my problem...then it would start to get hot if it sat for an extended time idling...had the radiator rodded out for $65 and it cured my overheating problem which the added airflow only hid the problem until pushed over the limit. My radiator was 60% clogged...When I put it back on I did notice I was able to put in quite a bit more coolant than previously...

If you are not going to reuse your brass plug you mind sending it this way? I can send you a few $$ for postage.

 

[vabiro]

If you are not going to reuse your brass plug you mind sending it this way? I can send you a few $$ for postage.

Doesn't Expedition Exchange sell these for something like $20? https://www.expeditionexchange.com/brassplug/

 

[edthediscoman]

I have pretty much been running the gambit on this one also. Lower the antifreeze levels as water is a better conductor of heat (as mentioned 50/50). You need some although I am currently down below that level, but it lubes the pump. OK. Take off both hoses to the rad, and give it a good flush. You can buy flushing agents, and run that yourself, or take it somewhere....sounds like you need option A there for now. Get the flush, run through the engine, then dump it all, and start over. With the hoses off, flush with a garden hose. While you are at it, spray the rad outside, as mine was full of mud and crap too. (I will probably get flamed from the purists on the flushing). OK, then, after driving, let the car sit, and check the waterpump housing for any leaks and the back of the engine block. You can hear a hissing sometimes if its back there. You could replace the T-stat, but sounds like that might be OK. Its probably either dirty rad in side or out. I have done the flush, the cleaning, the waterpump. Took for a drive the other day, and the level was the lowest on the gauge that I have seen since I owned the car. Good luck.
Ed

 

[garrett]

why not make sure the viscous fan is working first? do you hear it coming on during the climbs? i would start there. then dive into the rad once that is eliminated. of course i would start with tossing in a new t-stat for $10 and then a good flush. but make sure that fan is working first.

 

[Chris-St Louis]

Doesn't Expedition Exchange sell these for something like $20? https://www.expeditionexchange.com/brassplug/

Wow, way to overpay.


You can get one from home depot for a buck or 2.

http://www.hardwaresquare.com/sku453328340.html

 

[JohnC]

Wow, way to overpay.


You can get one from home depot for a buck or 2.

http://www.hardwaresquare.com/sku453328340.html

Chris, are they the same thread as the rad?

Ryan, just an FYI, I drove from Paragon to Tappan on Tues in my 96 DI and it was overheating (mainly on hills). I had the heater on full blast all day and it would still overheat.

I'm still trying to figure out what my problem is. I've checked my t-stat and it works fine (boiled some water and watched t-stat open). Replaced the Viscou fan with a good one (thank God for the Fan Clutch tool), new water pump installed a few months ago and new coolant temp sensor. Right now I think it's the radiator.

Almost forgot to mention, I have the brass plug and it leaks coolant thru the plug.

BTW Victor, you can get a new Rad here in the US for under $400 (original replacement).

 

[Chris-St Louis]

Chris, are they the same thread as the rad?

Yep, screws right in. Home depot. $2.00.

Or Lowes, whoever you like.

 

[JohnC]

Yep, screws right in. Home depot. $2.00.

Or Lowes, whoever you like.

Lowe's is closer and cleaner, HD is farther and real dirty..... I'll go to HD.

Thanks for the tip. BTW, is it EE approved?

 

[sven]

the rover actually didn't over head in the stop and go traffic. it overheated on the steep incline drive home, three miles uphill through winding paved mountain style roads.

Mine did the exact same thing last summer. Only overheats while going up mountains. A new radiator fixed this for good!

The funny thing was that my fan clutch never worked until AFTER a new radiator. My fan clutch is original..

Chris, do those HD plugs have the built-in rubber seal? If not, its not John Lee approved :smilelol:

 

[Chris-St Louis]

No Rubber Seal. But, Works Great. A little teflon tape and screw her in.

 

[Angel of Death]

Is the 4.0 radiator prone to collecting dirt and crap?

 

[vabiro]

Is the 4.0 radiator prone to collecting dirt and crap?

OH Ya! Like I said earlier, but not more than anything else if driven through dirty water. It was more than 20 minutes of continuous spraying before the water started to run clear.

Also, don't forget the AC condensor. It can fill up with crap between the condensor and the engine rad (there is only about an inch between). This stops the clean flow of air and pomotes corrosion where the dirt is held against the fins.

To really clean out properly, you should undo the two bolts holding the top of the rad and tilt it towards the engine. This will provide sufficient space to clean between the two.

Victor