Heating up / Overheating under load

[Josh]

So I was on a trip to Seattle yesterday and I was going about 85ish up I-5 on a hill and I looked down and my needle was a little more than 3/4 the way up the temp gauge. I let off the gas and coasted for a while and it started cooling down. Now whenever I'm putting load on the motor above like 60mph the temp gauge starts to climb. What can cause this? Broken clutch fan? Bad coolant? Blocked Radiator? Anyone ever experienced something like this? I have quite a bit more driving to do but it doesn't seem to be doing it if I take it easy on the gas pedal. I'm not really sure what happened... it was working fine before this happened, I'm not exactly nice to the go pedal all the time but its never overheated...

Thanks!

[Jason]

Whats the history of the cooling system? Have you ever flushed it? All kinds of crap can build up in the radiator and in the block that will reduce the systems effectiveness. What about the coolant itself, have you checked the concentration? Is the system holding pressure? Check all those things out.

Jason

[Josh]

system is holding pressure. coolant smells like crap.... not like coolant at all. I haven't flushed it as I've only owned it for a month or so. I'll flush it when I get home. I've been driving it around pretty hard and it hasn't been heating up... but I haven't really hit any major hills at any real speed. I'll report back after I drive 300 miles tomorrow :O

Whats really funny is the car now seems more peppy in town after it heated up some... maybe it blew out a bit of carbon or something from the heat? Hopefully it didn't damage anything though.

[77volvo245]

Make sure your not leaking any coolant

I think my temp guage on my diesel reads incorrect as well. In 5th gear at crusing speed it seems the temp reads above normal. I've replace everything and still not reading right. I have a 92+ 740 N/A radiator with an E-fan as well to cool it down. When I bought the car the body was sitting for about 9 years maybe that is why.

[Josh]

Nope the coolant tank stays full! Its just really weird! I think there's something blocking flow in the radiator.

[reed]

Dont forget to check pump timing. Or the thermostat.

[Jason]

Pull the top radiator support/header plate that bolts down over the radiator and condenser. There is a gap in there and my car had a bunch of crap in there. The coolant flush and replacement should be first on the list, then hose the radiator out too. With that top plate removed you can get directly at the radiator to clean the coils.

Jason

[Josh]

Will do, once I get home on Tuesday

[heavyequipment]

Probably not the fan clutch. That problem shows up worse at low speeds/stuck in traffic. My vote is for a clogged radiator, internally or externally.

Could also be exhaust restriction. The stock mufflers soot up. I removed my resonator and replaced it with pipe. Then I replaced the stock muffler with a straight-through (cherry bomb) muffler. It sounds OK and the boost pressure rises quicker (a lot) when I floor it.

These things use a lot of special hoses in the cooling system. I've replace a lot of the special ones with copper pipe fittings soldered together to get the bends and sizes right.

[Josh]

Well I'm going to search for a clog tomorrow when I get home. If it still does that after I flush the coolant and stuff I'll look at the hoses but I'm thinking its the radiator.