over heating dionostic

[laloquera]

My cb7 is over heating, fans are kicking on as they should be. Car hits red line at red light, but once I get going it goes down to normal. I have plenty of anti freeze in it. Park it, top radiator hose is hot and hard with a lot pressure built up and the lower hose is soft and not that hot. Thermostat?

[Fleetw00d]

If water is circulating, it should be hot at the top hose and cooler at the bottom hose (after cooling off in the radiator). System properly bled (bleed screw on top of thermostat housing)? Air near the temperature sensor for the dash (separate than for ECM) can result in high readings. Any idea how old the thermostat is?

[Kev1990]

Fleetwood I know your an expert on cb7s but that screw your talking about isn't for bleeding its to let you know when your filling the antifreeze that its reached a full level through-out the cooling system. Bleed your system with the cap off and make sure the radiator is completely full one time I had a friend come to me low on antifreeze just from where it hasn't been added or flushed in so many years her car would overheat at a stop too. When was your water pump - timing belt last done how many miles is on the car?


For the thermostat that's the cheapest route to start if its a aftermarket thermostat then definitely start there because I'm pretty sure OEM thermostats have a fail safe when they fail it keeps the engine cold instead of overheating.

[laloquera]

I did my TB & water pump a year ago. I just got swapping out my cylinder head a month ago. I did deal with a lot of corrosion, got a new thermostat housing along with the cross over pipe, they were both in pretty bad shape. I don't recall the last time I switch the thermostat? I did bleed the system with my heater set to high temperature and use a high level funnel that burps the bubbles out.

[laloquera]

Nailed it! No oil da water, no water in da oil. Swap out my T-stat, the hose and T-stat were bone dried on the exit side leading to the rad. I tried pushing down on it to get it open, it was stuck closed. Just wanted to share the 411 wit u all.
Peace!

[laloquera]

SON OF A BISKET! Im back with the same issue. Im not leaking change out my T-stat, double check for leaks, found none. My car heats up after driving 5miles and go's red line at red lights. I notices that it boils and it spraying hot coolant with steam through the reservoir vent.
Let me know what you think. Thanks

[laloquera]

I replaced my radiator cap, same issues. Help Help!

[Kev1990]

Sounds like possibly a bad head gasket , someone correct me if I'm wrong but when our cars have bad head gaskets it tends to boil the antifreeze reservoir and before we all jump to that conclusion there are some leaks that won't show unless under pressure or are hard to see leaking at all if you got the money take it to a shop to get your cooling system pressure tested or DIY with the kit at harbor freight. Keep us all updated please. Bad head gasket or water pump is what I'm thinking at this point anyways what brand water pump was used when you replaced it?

[jhondayaaj]

I would suggest you replace your head gasket and all necessary parts and send your head to have it cleaned, pressure tested and resurfaced. Sounds to me that you either have a warped head or a bad head gasket. Don't half ass it and just replace your head gasket.

Peace.

[laloquera]

Crap! I hate where this conversation is going, but I think you guys are pointing me towards the cylinder head being the culprit
I did a cylinder head straight swap from the JK about a month and a half ago, I was short & am still short on money & did not send it off to the machine shop. I was dealing with massive internal corrosion: t-stat housing, cross over pipe, hoses, I was cleaning and scraping all the hard build up from sensors.
Also, notice that the surface on the engine casting, where the head sits on was very corroded, the top brim of the piston cylinder wall were very rusted and practically gone. I use some permaflex on the gasket hoping it will hold.
The care ran great for a month and half. I don't have any liquids mixing. Im gonna check my compression tomorrow. I can rent a pressure kit to check the coolant system PSI. Dont reacall the water pump, got whatever was cleaver at the moment through Ebay.
That's where am at.

[laloquera]

Shit! I may need and another engine.

[laloquera]

Nothing new to post up. I have been adding water directly into the radiator and leaving the reservoir empty. I will not boil over, and takes half the time for the needle to go redline. Weird?
I've been procrastinating, I will do the compression check this afternoon and do more research.

[laloquera]

Nothing new to post up. I have been adding water directly into the radiator and leaving the reservoir empty. I will not boil over, and takes half the time for the needle to go redline. Weird?
I've been procrastinating, I will do the compression check this afternoon and do more research.
Also, I notice my cold start rev up was fluctuating, I have replaced my IAC in the past, the black rubber seal in it went shot. Can that be a possible heating issue as well, what do you think?

[laloquera]

I used Teflon tape on the threads on the following; condenser fan switch, coolant temperature gauge sending unit, & coolant temperature sensor. Im hoping Im not grounding this sensors out, if so I will take the Teflon tape off. What do you think?

[jhondayaaj]

Compression check won't do anything. Better to do a leak down if anything. Or even a block test should find the problem.